I think my main problem with the game is that it doesnt take enough chances. The arcade-style retro approach that the game takes is strikingly different from most games currently on the market, but the designers never exploit it in any remarkable way.
Cannon Spike proved to be a good time for a short while thanks to the two-player mode, but it cannot escape the limitations of being an arcade port. Generic enemies, bosses and environments might have made the game progressively unenjoyable, but insufficient continues and a steep difficulty curve made it unbearable relatively quickly. It's amazing that after I set my sights low, expecting nothing more than a fun multiplayer experience, Cannon Spike still managed to disappoint.
According to ESRB, this game contains: Animated Violence