Good idea, but the execution is a bit lacking.
Controlling the character doesn't feel all that satisfying, and firing at the enemies feels more like you're getting lucky than you using the mechanics in clever ways to beat your foe.
Being able to use the environment would be nice. Like being able to grab things and placing them to function as "aim points" so you have a bit more choice in where you aim.
A ray showing the bullet trajectories before you fire would be great too.