I don't understand the confusion people seem to have over what the game is. This question gets asked a lot, but I just don't get it.
Maybe it's indicative of how different the perspective is on games these days compared to people who are more familiar with character action games? I dunno.
The game is a 3D beatemup where you pick an Autobot to control and play through 7 stages bashing Decepticons up, moving through a stage, bashing more Decepticons, bashing mid-bosses, bashing a stage boss, and then proceeding to the next stage. Doesn't seem confusing to me...?