I don't understand what the controls are. I tried WASD and arrow keys and spacebar but couldn't seem to make anything happen on the screen. I like the graphics though, although the menu buttons don't scale with the screen size so I had to figure out where the buttons really were, luckily they became visible when hovering over them so that helped.
Edit: I spam-clicked when the game started and managed to kill 2 things. I think whatever the control is for the targeting reticle seems to be drifting away because after that it was offscreen and I couldn't affect anything again.