Way too short and very little variety, ruin what could've been a very good game.
The other thing is the special moves make the game a bit too easy. After a few kills you can use a special move that kills everyone in a room which seems a bit unfair. The game's way of balancing the scales? Just send it wave after of bad guys which seemingly never end appears to be the answer. With the environments being pretty small it can get a bit boring as there aren't many ways of killing the bad guys.
It looked very stylish and whilst it lasted it was fun enough but it could get pretty monotonous once a room filled up with bog standard enemies. On the lower difficulties it's possible to just build up to unleashing 'barrage' and then use the invincibility it offers to get up close and personal to the games bosses and they can't hurt you whatsoever. There's not a lot to the game - just hold the fire button and wait until everyone is dead. It is an incredibly short game and should only be played in small bursts but it is a fun way to pass some time and is a good way of getting rid of stress as there are some many bad guys to take down!