PraetorianX: I tried to put the voice in the game (spent more than a few hours on it), but it just didn't fit. If I had started with the voice first and added other sound effects on top of it, it probably would have worked better. The music in the trailer is based on one of the gameplay songs, but it's not the same. I always create trailer music based on existing gameplay music, but the pacing for gameplay vs. a trailer is significantly different, and the music was also modified to be in tune with the voice.
killercow: Super Crossfire actually has IAP, but it's not very obvious and completely optional. I'm trying to avoid IAP in my games, but I have to admit I have considered it for future games. So far I haven't needed to do it. I promise to be as un-evil about it as possible if it ever happens.
If I port the games to Android, those versions would be more likely to have prominent IAP than the current iOS versions (any Ouya versions would likely be an exception) for obvious piracy-related reasons.