So there are a lot of these types of shooters, it's been a while since I've played one. I thought for a made-from-scratch it was fun. I do have comments on things you could improve. And before you think badly I've got so many comments, it's because there's potential for a really fun game here.

1) The keys are too spread out. If I'm using WASD to move, and the mouse to aim, it's not great that i have to look away from the screen and stop moving completely to find "H" and "P" If you're going to bind these, make them "Q" or "E" But better yet, make the chests and shop an icon on the screen I can click.

2) Enemies only spawn from 1 side of the screen for the first 15 levels, it helps make the playing field bigger, but reduces the complexity of the game and makes it a bit less exciting. As the enemies get bigger, I'm thankful for this, but it takes a long time to scale up to multiple spawn points, and the map gets too small too quick. Would make the graphics smaller and the playing field bigger.

3) I got 15 levels in before I realized I got a free chest every wave. There need to be an icon, or to have the chest menu pop up when i beat a wave. Or better just automatically open the free chest when i beat a wave. I kept forgetting about these.

4) and "X" close button i can use the mouse with on all pop-up menus.

5) I was getting repetitive items from chests, like the boomer 3x from chests. Which basically means it does nothing. I would recommend one of a few options here:
5a) add a check that IF I already have the weapon I pulled from the chest I get gold instead. This gold could be based on my current wave, or how many upgrades for that weapon I have.
5b) add a check that IF I already have the weapon I pulled from the chest I get an upgrade for that weapon instead.
5c) add a check that IF I already have a weapon, it gets removed from the possible pool of what I can draw from chests.

6) Counters to my current level of each increment of weapon upgrades in the shop. It looks like I can only buy so many upgrades. If this is the case, when I've fully upgraded a weapon upgrade, it should gray, "X", or graphically look unavailable or maxed out.

7) Enemies scale slowly, but their gold never goes up and they don't shoot back. Overall income scaling is super high, but if you balance the game for smarter/required use of other weapons, there won't be anywhere near enough gold, maybe gold is based on wave# AND enemy type.

8) I like there are so many weapon choices, but currently there's 2 weapons I'm constantly using, so the rest seem excessive. Perhaps think about how to adjust levels so that a certain weapon is more effective than others. This way, you're encouraging the player to upgrade across the entire board and not just focus on the shotgun and rocket launcher. Possibly focus this idea on boss fights where a rocket launcher might not be as effective as a sniper rifle, that sort of idea.

9) Even upgrading speed, once I get hit by a red enemy I cannot dodge them and they kill me. Would think about adding a speed boost when I get hit, or that enemies immediately around me get stunned so I can actually run away. Currently if i get hit once by a red enemy, I know 100% I'm dead.

I really do like the game, and it's it's current form, it just builds a little too slowly. Keep it up!