People are still going to have to mine 100 years to get a sword of uberness no matter what weird new coin you invent, in fact they will probably have to mine even longer mining some previously unheard of coin no-one except those players has any use for than mining bitcoins or litecoins etc.
Bear in mind too that by having them mine at your pool, they can mine Bitcoins, Namecoins, Groupcoins, Devcoins, Ixcoins, I0coins, Ixcoins and Coliedcoins all at the same time, plus if you wish a whole bunch of strange new coins no one ever previously heard of.
In fact if you can get enough players to actually make a chain secure - that is, get enough mining power to secure a chain - they can also mine Britcoins, Botcoins, Canadian Digital Notes, CZech Bitcash, General Mining Corp, General Retirement Corp, bitNicKeLs and United Nations Scrip. All at once courtesy of merged mining, with still the ability to add more to the repertoire.
That is because if you can get enough mining power to secure a chain, all those chains can move back out of the Open Transactions format to which they retreated in the face of the hideous expense of securing a blockchain to a blockchain format the amount of mining power players of games are able and willing to provide.
If you still insist on discriminating against people using GPUs, you could also look into applying merged mining patches to litecoin and other "CPU friendly" coins so that all of those can be mined at once. How to make them even more "CPU friendly" is something all of them are presumably interested in so if you do figure out some way their anti-GPU bias can be increased they will probably all be interested since that is afterall their own reason-for-being too. They are thus striving to be the coin you are looking for and merely await your upgrade patch to bring them into line with your goal while also thereby brining them back in line with their own goal.
It seems though that you are basically just uttering self-contradicting bullshit to try to justify yet another pump and dump since unless many many many more computers than just those actually playing the game mine some new shitcoin it will be far too vulnerable (*) but the more people that mine it the less uberswords each one will be able to buy with the generated coins.
How many uberswords per block are to be mined? Or how many uberswords per week? Or how many uberswords per month or per year?
(*) You could however read up on solidcoin and the various threads on "stake" to see how a spectacularly shitty series of shitcoins secured chains despite almost no mining power and how some theorists theorise a newer better solidcoin using distributed consensus instead of divine right to allocate special powers could work.