I like it. The art and the style.
Also it is satisfying to reflect bullets at the right time.

I also had an issue with not working controls. I restarted the game and it was okay but then it happened again and I just continue playing standing still ) 

I think you just have to constraint the mouse inside the game or lock in the center. Most of the game negines has this functionality. Not sure for GameMaker though.

Very fun take on the survivor genre with a surprising amount of depth and progression.

With randomized upgrades between levels and a graphical overhaul I could see it becoming a paid game.

The shields not moving with you when bashing feels a bit weird, personally I'd change that.

Movement controls were not working but still playable. It would be nice if the enemies were a bit faster.