It's simple - but the action is pretty fun, and it's deceptively tough. Having to pick your shots, always being worried that every shot might be a wasted shot, learning the layout of the facility and doing better each run is a really cool loop. Gameplay is pretty tight, it's simple and it does what it does well.
I'd almost say having that repetition baked into the game narrative could be cool, with having to mentally map out the environment and find what you're after, and get closer to the goal with each successful run.
My only critique is a lack of a visible health mechanic - maybe a more survival-horror aspect, with having to scavenge health kits and such?
Either way - pretty cool idea, pretty decent execution! Pretty fun lil action game.