Coinballer - An open-source multi-player Bitcoin gambling game.

[cryptofrka]

So any troll can delay our bet for a few cents per day

Based on the rules, not really.

The rules say:
The game ends when a certain number of bitcoin blocks have passed without a raise that is equal to or exceeds the maximum bet. This length is configurable.

Haven't tested if that is actually true ingame though.

But yea, if you start with pennies bets, someone can raise contnuously just to annoy you

[LoyceV]

without a raise that is equal to or exceeds the maximum bet

Anyone can deposit to the highest funded address, thereby raising the maximum bet.

[cryptofrka]

Anyone can deposit to the highest funded address, thereby raising the maximum bet.

I understood that differently, for example if the max bet is 1mBTC, a bet of an additional 1mBTC or more needs to be made to restart the timer.

But yeah - haven't tested it so I'm not really sure. Your logic makes sense as well.

[darkangel11]

without a raise that is equal to or exceeds the maximum bet

Anyone can deposit to the highest funded address, thereby raising the maximum bet.

If it works this way the game is open to cheating where a player gathers a group of people to watch the game and keep raising bets by depositing dust to the same address. I bet it would be possible to make a bot to do it automatically. Once the number goes up without the bot depositing anything, the bot adds to the pool from your wallet to make sure you're always on top, even when you sleep
The same bot could also extend the game forever by adding one sat per hour or something. Of course nobody will bother to do that when people are fighting over pennies in a local game, but the possibility is there.

[FatFork]

It looks like many members have already identified several issues with the game. However, the most concerning issue for me is that I believe I have discovered a critical bug in the gambling mechanics. I'm curious to know if anyone else will experience this problem as well.

In the following part of the review, I will be discussing Game 23, which was a completed game between me and cryptofrka.



Game flow:
cryptofrka funded 8000 sats to this address: bc1qgdh69sd0ldyapk3ux8kztkhfpx25le7lt6fjt0. I was supposed to send a certain amount to the address: bc1qdm8mnf5mfnhw6447dkev6s3fze63333vch5h28, but unfortunately, the transaction wasn't confirmed before the deadline due to a low fee. However, after the game round ended, I received an amount of 7840 sats to my payout address in this transaction.

If my understanding is correct, the system awarded the entire pot amount (minus the 2% fee) to only one participant (me), despite the game being set up for two winners (which is evident from the screenshot). Furthermore, I won the game even though I didn't even participate in it. I'm unsure if this was a random occurrence or due to my address being first on the list, but either way, this is not the intended behavior of the system and I believe it to be a serious bug.


*OP, this is my review, although I'm sure I will contribute to this thread more in the future and express my opinion as the game develops further.

[virasog]

The player who has contributed the most money to the pot at the end of the game wins the whole pot, minus a 2% fee for the host.

So does it mean that people wil contribute to the pot and in the end only ONE person will win the whole pot and the rest all contributors will lose the moeny  
Also, this mean that the game does not depend upon luck but the one who is able to contribute most money will win in the end. This favour the rich as if you have a lot of money you can win the pot. Anyone with limited money will lose the game    This game is for the rich people ?

[2double0]

The player who has contributed the most money to the pot at the end of the game wins the whole pot, minus a 2% fee for the host.

So does it mean that people wil contribute to the pot and in the end only ONE person will win the whole pot and the rest all contributors will lose the moeny  
SNIP

No, because OP has confirmed that you can decide how many winners will be there in a specific game whenever you create a game. I was also confused about this but I have even seen 2 players in 1 game and both of them getting something because the creator chose 2 winners (LoyceV's game you can check in this thread).

[FatFork]

The player who has contributed the most money to the pot at the end of the game wins the whole pot, minus a 2% fee for the host.

So does it mean that people wil contribute to the pot and in the end only ONE person will win the whole pot and the rest all contributors will lose the moeny  
SNIP

No, because OP has confirmed that you can decide how many winners will be there in a specific game whenever you create a game. I was also confused about this but I have even seen 2 players in 1 game and both of them getting something because the creator chose 2 winners (LoyceV's game you can check in this thread).

In theory, that's the way the game is supposed to work (or at least, that's our understanding of it). However, it doesn't seem to be living up to that expectation in practice. We'll have to see how Loyce's game turns out before we can say for sure. In the meantime, you can check out my review of Game #23 in the previous posts.

[jackmurray]

I believe I have discovered a critical bug in the gambling mechanics. I'm curious to know if anyone else will experience this problem as well.
...
this is not the intended behavior of the system and I believe it to be a serious bug

Yes, you found a critical bug. I've fixed it here.

I've sent 0.00121738 BTC to the address on your bitcointalk profile as a reward for pointing this out. Thank you.

[Edwardard]

We got some really cool testers down the line. Keep it going guys

The site works on Tor without complaining or captcha. I like the simplicity.

Yep, and btw if anyone wants, they can access the site through .onion link as well provided below.
Link: ba7lbmv2ahkeh6rptw4nicj3au7njzubua3nlopwdiv4h5hdxjoolkid.onion

I really dislike giving negative reviews

Critical reviews are welcomed if they are to the point. Everyone feel free to point out any major issues you got. I agree with you that a short youtube video explaining the game will be much appreciated (as visual info is grasped better than the text).

I believe I have discovered a critical bug in the gambling mechanics. I'm curious to know if anyone else will experience this problem as well.
...
this is not the intended behavior of the system and I believe it to be a serious bug

Yes, you found a critical bug. I've fixed it here.

I've sent 0.00121738 BTC to the address on your bitcointalk profile as a reward for pointing this out. Thank you.

Good find @FatFork and congrats for the bonus tip , well deserved !

[jackmurray]

There were a few people saying they want to join an open game, rather than have to create a game with players' addresses.

For these people wishing to join an open game, you may prefer https://satoshiauction.net instead, which is a similar game, but every game is open to everybody to play.

[LoyceV]

Let's have some fun then LOL

It looks like you made a deposit that didn't show up even after 52 confirmations.

Fees spiked yesterday. @jackmurray : can you check the above transaction? What happens to a deposit if it gets confirmed after the game ended?

[BitcoinGirl.Club]

Length of time between last bet and deadline   144 blocks.

So any troll can delay our bet for a few cents per day

The payment confirmed but the amount still does not reflect on the site. I am taking a note about it. May be a bug?

But yeah - haven't tested it so I'm not really sure. Your logic makes sense as well.

I think once the deadline block height confirmed it will activate and send the winners their coins. But question is what will happen when there are unconfirmed tx?
They are not taking it in calculation until 6 block mines. But if they take it in consideration before the tx confirms then there is a chance for double spending too.

In our case game 22. My tx confirmed already but it's not showing on the site. Considering it's not showing yet, the prize for both of us are 0.000049 BTC each where it was supposed to add more 0.001 BTC with the total except the 2% charge.

Update:

Let's have some fun then LOL

It looks like you made a deposit that didn't show up even after 52 confirmations.

Fees spiked yesterday. @jackmurray : can you check the above transaction? What happens to a deposit if it gets confirmed after the game ended?

Yes, just read LOL

[Coin_trader]

But they also have to spend few cents on TX fee (even when they use fee rate 1 sat/vbyte) and open their wallet every time they create a transaction. IMO it's not very practical attack.

As I understand the betting rules. The only allowed bet is the max bid made by the winning user. So if someone bid 1mbtc then no one can bid lesser than that amount to become a valid winning bid for the auction.

This is what I understand on the game design to avoid spam bids just to extend the duration. @jackmurray can you verify this?

[cryptofrka]

But they also have to spend few cents on TX fee (even when they use fee rate 1 sat/vbyte) and open their wallet every time they create a transaction. IMO it's not very practical attack.

Agreed, you can bot it though just to annoy people.
If I understood the mechanics, only a higher than current max bet would restart it - and that's the way it should work IMO.

______________________

Yes, you found a critical bug. I've fixed it here.

I've sent 0.00121738 BTC to the address on your bitcointalk profile as a reward for pointing this out. Thank you.

Good that this was fixed already, I just came to confirm that although I'm the only one that bet on the outcome eventually I walked away with 0 BTC

Is it fixed for all currently opened games, or will it be fixed only for the newly created ones?

[LoyceV]

As I understand the betting rules. The only allowed bet is the max bid made by the winning user. So if someone bid 1mbtc then no one can bid lesser than that amount to become a valid winning bid for the auction.

If someone bids 1 mBTC, and someone else bids 1.01, they can play ping-pong by adding small amounts.

[ABCbits]

My review about Coinballer (Done)

First visit

Using Tor Browser, i visit Coinballer website. I don't see annoying "security check" or CAPTCHA which is a bit nice compared to few casino i've visited. The website design is extremely simple which reminds me of 90's website, although slightly modern design would be great and could attract more people. I have slight positive first impression.

Just like other member, i have difficulty understanding the rule. I had to re-read the rules few times and read discussion among member in order to understand the rule. Even so, there's one point i misunderstood (more detail below). So it'd be great if short video or example of game session with some explanation is exist.

Exploring other page, i didn't find few important page such as FAQ, ToS (Terms of Service) and PP (Privacy Policy). Many people would either perceive it as red flag or doesn't take your casino seriously. You really should add those page since it also could save you from answering similar question many times.

As open source user, it's nice addition that the website is open source. But most people either don't care or don't know the benefit of open source software, so adding one/two paragraph explanation about it could give user better impression. And while we're at it, the "About" page should include another ways to contact you (such as email address or this Bitcointalk thread).

Play a game

Since the game require you to include Bitcoin address of all players in advance, i decide to include Bitcoin address of all reviewer and see who joined. It's more convenient and took less time compared with contacting each potential player where. As you can see on game 21, i set it to have 10 player, 3 winner and 576 blocks (about 4 days) length. Initially i mistook 576 blocks as length of whole game rather than length between last bet and deadline. Had i known about it, i would set it to only 288 or 432 blocks (about 2 or 3 days).

Checking other games, there are many finished game and unfinished game with empty pot. It'd be great if list of finished game only can be seen on different page. And since there are many unfinished game with empty pot, personally i'd like the website to emphasize game with non-empty pot.

Now about UI/UX, there are few lacking things. While now we know 6 confirmation is needed, it'd be great if the game show transaction/balance which doesn't have 6 confirmation yet. It'd be nice assurance for user that the system already detect the transaction and they send Bitcoin to correct address. The website also only use block height/total block count as time reference. Adding different time unit such as "576 blocks (4 days or ended on 10/01/2023 10:00 AM)" would give user better idea and saving their time from using calculator and looking at calendar.

Game 21 finally finished after 4.5 to 5 days since the creation. I sent 10K satoshi during the game and received ~11K satoshi in return which is nice. I briefly checked the transaction on certain Bitcoin block explorer and found out each transaction only send Bitcoin to one winner. I would recommend you to perform batching in the future to reduce satoshi spend on TX fee.

Conclusion

I have not so positive experience with Coinballer. The game itself isn't really fun since i have to contact people in advance, which is cumbersome when people around you isn't willing to bet with real money. I also feel the only suspense/adrenaline comes from player who're willing to keep make a raise. But take note i'm not gambler.

From UI/UX and marketing perspective, some effort is needed to attract average player/gambler. Aside from what i've mentioned above or already mentioned by other player, here are few additional recommendation.

• Coinballer source code has no license yet, so you should add one. MIT is simple and popular option, but AGPLv3 also works if you want to put few restriction.
• For game with multiple winners, having option to share the pot evenly or based on deposit amount would be great option.
• Let player know that amount on "Currently each winner will receive" doesn't consider Bitcoin transaction fee.

[FatFork]

Yes, you found a critical bug. I've fixed it here.

I've sent 0.00121738 BTC to the address on your bitcointalk profile as a reward for pointing this out. Thank you.

Good that this was fixed already, I just came to confirm that although I'm the only one that bet on the outcome eventually I walked away with 0 BTC

I wanted to be fair, so I sent 0.6mBTC (half of the bug bounty) to your wallet. We both played a role in finding the bug, so I thought it was appropriate to split the reward.

Is it fixed for all currently opened games, or will it be fixed only for the newly created ones?

It appears that the issue has been fixed for everyone. Based on the outcome of Game #22, it seems that LoyceV and BitcoinGirl.Club shared the pot. However, upon further inspection, it looks like the second deposit was not taken into account in the total balance. This could potentially be another bug, or at the very least, a flaw in the software that needs to be addressed.

@jackmurray, perhaps the simplest solution to this problem would be to automatically return all transactions that are confirmed after the deadline to the sender (minus the transfer fee)?

[LoyceV]

Review

First: it felt more like testing than reviewing. I know the site is still in development, but in my opinion there are still too many problems to go live. The Rules don't cover some of the possible scenarios I can think of. My first impression after being happy to see a new type of game was confusion. It took me a while to realize for instance sniping isn't possible.

I started my Review yesterday:

I'm not much of a gambler, because I don't want another addiction in my life. But I like games, and Coinballer looks like an entirely new concept.
The site works on Tor without complaining or captcha. I like the simplicity.

I can complete my Review now that (my) Game 22 ended. See:

It took me a while to realize a game with 2 people and 2 winners makes no sense: you'll get back 49% of anything you deposit, and so does the other player. That means there's no incentive to deposit anything, but it did it as a test.
There was a problem with the game: one of the deposits wasn't registered, despite having many confirmations before the game ended. The final prize was based on only the first deposit, the second deposit is still unaccounted for. Needless to say: this shouldn't happen. Update: it's fixed.

Suggestions

• I get that you don't want to work with unconfirmed transactions, but can you at least add a notification when one of the addresses has an incoming deposit?
• Add a warning when someone creates a game with the same number of winners as players. Such a game makes no sense.
• The maximun number of blocks 525600 between the last bet and the deadline is very large. Not everyone knows blocks take 10 minutes, and if someone accidentally sets it to 10 years, they'll complain. I'd say lower the maximum number of blocks. See Game 27:
  
  

• With multiple winners, can you (optionally) make their prizes pro-rated? So if there are 5 players and 2 winners, each winner gets a prize depending on how much they deposited.
• Ask for less confirmations, waiting an hour on average for 6 confirmations makes the game very slow. And most websites don't require that many confirmations, usually 1 is enough unless there are large amounts involved.
• Add (optional) labels to the addresses when creating a New Game, to make it easier to distinguish addresses for the players. Or at least number the rows with addresses.
• The "Current confirmed block height" is 6 less than the current block height. I get that the difference is 6 confirmations, but this can be confusing. Example: if the deadline is 800000, and the current confirmed block height is 799995, it's already too late to make a deposit but that isn't clear from the game.
• I know it shows the current block height and the deadline, but comparing large numbers isn't trival. Can you show a countdown for the remaining blocks?
• I get that you don't want to work with unconfirmed transactions, but can you at least add a notification when one of the addresses has an incoming deposit?
• Maybe you can you add a FAQ with some screenshots of finished games, to make things clearer. And add more information, what happens for instance if a deposit confirms after the game ended? Will you return it?

Game play
I haven't seen a game that's attractive to deposit if nobody else deposited yet, and that could stop people from starting a game.
Takes for example Game 21:

This game has a minimum of 3 winners out of (up to) 10 players. If you're the first to deposit, and nobody else deposits, you get back less than 33% of your deposit. That's a huge risk to take!
If 5 others have deposited (that's the current state of the game in the screenshot), you'll need to deposit at least 0.00010000 BTC to get a prize (or 1 sat more to eliminate another player). That a much more attractive bet.
If there's only 1 winner, it's still not attractive to be the first, but at least you'll get back 98% if nobody else deposits.
I can't think of a way to improve this, and it may be inherent to this kind of game, but shouldn't a game be attractive from the start?

[bullrun2024bro]

Coinballer.net Review

I have looked at Coinballer's service repeatedly over the last few days and can give the following review:


Domain:

First of all, I have to say that I find the domain very appealing. Although it is only a .net domain, the name Coinballer.net is easily recognisable and stays in your head once you have been on the site. Good job. IMHO, it is a key point if you want to attract new players/customers in the future.

Afterwards I checked the site (as I do with every new service I visit) once on virustotal and again everything looked fine. Very nice. Testing could start straight away.




First Impression and Game Rules:

The first impression of the website is simple and clear. That is good. You can find your way around the clearly laid out main menu. The concept looks new and unique (very cool!). However, you are soon faced with the question: What is Coinballer exactly and how does the game work?

And this is where the problems start, unfortunately. If you click on the menu item "Rules" (https://coinballer.net/rules), the rules are worded so briefly that an "every day user" is completely unable to follow. I showed the website to a friend of mine who knows very little about crypto. And he doesn't understand a thing.

And if a user does not immediately understand how things work, he will only very rarely take the time to do so (Remember: Most of us are no tech geeks, we need explanations!). As a result, he usually leaves the website and Coinballer loses a potential player.

IMHO, that's why the "Rules"-section urgently needs to be reworked! Preferably with a detailed (!) description that includes either screenshots or videos of a complete game sequence.

Furthermore, pages such as a FAQ, Privacy Policy, Disclaimer or ToS are missing completely. In addition to that there is no support or contact form in case of problems during play. Okay... there is a short about page with a link to a LinkedIn profile and a note that the website is open-source, but IMHO this part also needs some rework. Don't forget to add an email or this Bitcointalk thread. If you want to do some support here (plenty of other projects do that too!).

Play on Coinballer:



I wanted to start a quick game (Game 30) that ends in 10 blocks, but then realised that at least 12 blocks are needed. Unfortunately, nothing was written about this in the rules. But there is an error, if you try to go below 12 blocks.

Error: An invalid length was provided. Length must be between 12 and 525600 blocks.

Furthermore, the maximum value of 525600 is quite high. Inexperienced users could accidentally start a game that will take months to finish. However, the high maximum also gives the possibility to start games that run over a longer period of time. As a provider, you have to weigh this up carefully. If a long game period should also be possible in the future, I would include a disclaimer that tells the player:

"Be careful, you are about to start a game that may not end for several months/years!"

In addition, I would also add the note that transactions require 6 confirmations on the Rules/FAQ pages. Moreover, it would be helpful if transactions that do not yet have 6 confirmations are also displayed somewhere on the Game page (e.g. TX bc1... - Betting Amount 0.001 BTC - 3/6).

Another cool feature would be a big button/text letting the players know how much is in the pot and how much the winner would receive (prize money minus fees). This of course needs to be updated once a new bet is placed.

In addition, it would certainly make sense to move all played games to a separate page (perhaps "Played Games" or similar). Of course, later on you could also add pages like "Highest Games/Jackpot", "Most Players", "Most Bets". If players see that a lot of BTC is being wagered on your site and that there are a lot of other players, this should act as a great incentive for many to try your service.

Conclusion:

My experience with Coinballer is mixed. The product doesn't seem mature yet and it might need some work to turn this website into a real game that people actually play. Nevertheless, I find the idea exciting and with dedicated devs, a great product can certainly be developed here.

I also think the basic game idea is plausible. If players are willing to keep increasing their stakes, the pot can grow pretty quickly. And then players are likely to bet more and more to win the game (We all know this from auctions, where the bidders go into a frenzy and keep bidding each other up - even if they were initially only prepared to put down a much lower amount.).

The UI/UX needs to be reworked, of course. I don't want to list all the points I mentioned here again - but I think my review and the other reviews here will show that there is no shortage of points in need of improvement.

Anyway, I hope my review helps and you guys will create a cool game in the long run. Good luck!