Hey, just gave it a spin. I'm working on a topdown action game myself.
First off, you should make a standalone .exe - the installer allmost got me turned off. (Just select 'standalone executable' from the dropdown, when GM asks you where to save the file to.)

Aside from that I found the player movement quite a bit too fast. Felt a bit slippy to me. Graphics, UI and Audio and are still placeholders I guess, there is a lot to improve on there.

At least you have different AI types, shooting and 'jumping' enemies, I like that. I didn't play much though - limited time.

It might fit well in the concepts area to get more 'public' feedback, I don't want to judge it...

Here is a screenshot for making a standalone exe HERE[imgwiz.com]