Mohasanie, it seems a bit silly to go and get an iPhone 5 as an alternative to a galaxy s2 simply because of gaming. Most games (and by most i mean just about all) are made with android and ios in mind. This goes for most apps in general actually. The only difference i noticed is that ios apps are sometimes paid whereas android apps are usually free. This will become true for windows phones as well as soon as it picks up (if it does).
There are a handful of quality exclusives for ios devices...a HANDFUL!
You really should be looking at what phone do you like more. As a fellow owner of a GS2 i would say wait a while longer for a significant upgrade. And if you absolutely don't want to wait rather look at all the features of the phone and then compare it. Buying a phone based solely on gaming seems really silly.
Mobile games are sub par in general. The reason you not happy with your S2 gaming library is not because you only have access to a shitty library but rather because there is only a shitty library. Moving to windows mobile OS will make this situation WORSE. Moving to ios will just about keep it the same.
I hope i actually helped with your question. Other people in here just seem to blurting out their preferred platform,.







