Hey, great demo! First of all, the movement is extremely smooth and easy to pick up: in 2 minutes of gameplay, I had already mastered it. And I can see that you've put a lot of effort into making the menus look good :) So yeah, it looks really promising. I'm sure that if you keep working on it, this demo could become a really great game.
Of course, this is only my personal opinion, but a lot of things still feel a bit off:
- The game is way too easy: I am completely overpowered even though I never switch weapons and I don’t take the time to buy any upgrades.
- The forced break that the player has to take between waves really breaks the immersion: Right now, every time a wave ends, I have to go to the center of the arena to start a new wave, and before starting it, I have to check a new weapon manually (and 90% of the time it is worse than the one I currently own). And there is a shop, but I just stopped going there; it doesn’t seem to be useful since I’m already overpowered. So yeah, you should probably simplify the upgrade system a lot. I won’t tell you how to do it because it all depends on what direction you want to head in with your game, but right now, it breaks the immersion.
- And finally, I would love to see a little more enemy variety. The game is getting boring very fast. If you don’t know how, you can take inspiration from the first DOOM game. Mark Brown has made a great video about this on his channel Game Maker’s Toolkit.
Sorry if I seem rude in this comment; I really just want you to succeed, and I’m convinced that just telling you to “keep going” won’t help you as much as a real critique of the game’s design.
Anyway, I hope that you’ll have a great day and that my advice has been at least somewhat useful.