-That is a big "perhaps". I'm not good with playing FPS games on gamepads so I can't add a good support for it. It would also need to involve some kind of auto-aim which is a pain to get right. I might add _some_ support for gamepads, but so far Xpadder is your only way. The active stage of development is over anyway, it's only bugfixes now.
-I don't really understand what you mean. Camera shaking when taking damage? Unlikely. camera shaking when moving? Already there.
-You can add more sprites by using state machines. I just didn't have time to write any manual on this but I hope to get at least something in near future.
-That is unlikely. Te engine is made for windows only and compiling it for Android would take too much time to get anywhere.
-That is something I haven't even thought about The engine is made for old-school single-player only games and would hardly be flexible enough for good balance for co-op. Also, a pain to make. Though not impossible.