Pretty fun.
There's nothing too special about this game. It's fun and somewhat challenging, but becomes boring and repetitive after the first few levels.
I think It's way too easy in the beginning. The CPU was shooting at the ground and throwing grenades that eventually landed at his feet. Then the difficulty elevated quickly. (A little too quickly in my opinion) The CPU started throwing near-perfect grenades and was making headshots with ease. In my opinion, a game's difficulty should raise in small increments over time and this process should be near impossible to notice.
Alos, I think that better/less repetitive music would have made this game better. No one wants to listen to the same annoying song over and over again while they play/read instructions.
Other than that, the game was pretty fun and had a good concept. It wasn't terrible, but it wasn't amazing either.
P.S. Blood always helps.