Here you can see the original thread by the author regarding the Ponz.
https://bitcointalk.org/index.php?topic=668391.msgNow, about actually getting some bitcoins, I did have the great experience of earning a couple of mili BTC in the summer playing the Ponz and ending in one of the first 3 places, about three times aa week. (and I certainly had a lot of fun playing it).
About a month ago, 3 weeks perhaps, the author apparently stopped running the high score register because (it is hinted or explained in the referred thread) he wanted to develop different business models for the game.
I have not tried the other games you mention, but my impression is that opportunities will come and go to actually earn some crypto coins. The Ponz appears to be on hold regarding that...
... and I still play it for fun (great that it still works in my oldie iPad 1). While I have not set myself to monitor net traffic on my wifi or otherwise attempted to watchdog what information the game might be sending (presumably mining activity), I strongly feel malware is not the case for that game.
If you're a newbie like me, you should get the best opportunity to get some free coins by watching the activity in several sub-forums here, and take on some of the opportunities... some providers open new exchanges or pages and give you some free coins by registering (some do, indeed offer that without dirty tricks or buts). Again, on the topic of games, particularly for the iPad, the Ponz did work for me as a way to earn a few mBTCs, and I hope it will be working again like that in the future.
S.
