Due to the level design, when you're placed in a bottleneck with enemies on both sides the game becomes a test of how well you can abuse faults in the AI's programming.
The game is good, but the campaign should have lasted half of what it did. Otherwise, it gets a bit grindy.
my fingers (middle and ring of right hand) became sore after playing this too long, now its next to impossible to get the last achievement! D: (75 combo)