I really like the art for this game, it looks really cool! And you game page looks awesome as well. I also really like the concept of losing skills from a skill tree.
Unfortunately, I think the gameplay is missing some depth. The combat basically comes down to facing the right direction and spamming the mouse button. You could maybe add some depth by allowing the player to take cover, or by shooting where the mouse is pointed instead of straight.
The jumping is also really floaty. You should probably increase the gravity. I usually start with 20 and sometimes even go up from there. It tends to feel much better that way.
I'd really appreciate it if you would have a look at my game as well, and be sure to download the smaller version.