Very, very difficult to maneuver in.
It has the potential to be something worthwhile, but a lot of technical problems mar this entry. For example:
It's extremely difficult to maneuver and move around due to very, very constricting environments.
It can be difficult to know whether or not a shot lands on an enemy, and even then difficult to actually hit them due to the constricting landscape.
Finally... getting hit. This was my biggest problem. When you're hit, you slow down to almost a snail's pace, making escape almost impossible.
Work these out and you could have something worthwhile!