Hello and welcome to Feedback Quest 9! My name is Hythrain, and I'm one of the hosts for this lovely event! I'm also one of the streamers, so both the game and this feedback are being done live! If you want to see the see the VOD, let me know and I'll link you to it when it's uploaded to YouTube!
While there have been a few vampire survivors during this event, this is the best one I've played so far. It has amazing music and a lot of weapons feel great to use, making it a lot of fun to mow down monsters. It also gives me some slight DOOM vibes, but this is more in the aesthetic I see than in the gameplay.
However, I'm not a fan of starting levels where you simply cannot win, especially when it happens when I'm still trying to figure out the controls (more no the controls in a bit). I'd rather see a first level that helps the player get used to the game, THEN give them the impossible level so they reset and begin a proper run. Otherwise, you're beginning the game with an instant death which can turn some people off.
Okay, brief note on the controls. Before I started, I decided to see what the controls were supposed to be (instead of just jumping in and seeing how well the game teaches me on its own). For some reason, when I went to see the controls, the game somehow jumped me direct to the gamepad controls. I thought this was a controller only game, until I noticed the game display using keyboard to interact when I bumped my mouse. I'm not sure why it went to the gamepad controls on its own, but there could be something going on there.
Onto other stuff, I want to recommend changing how you display text in the game. More specifically, you should remove the gradient you use on the font. Gradients on a bitmap font can be hard to read, especially if said gradients go towards whatever colour you're using for backgrounds. In this case, your tooltips have a dark, slightly transparent background, which makes the text harder to read (especially if you're moving fast). I'd say either you should remove the gradients and keep everything to single colours, or you keep the colours you choose for each gradient at a higher colour than what they are now.
I'll also say that I'm not a fan of money despawning in these sorts of games. Due to the sheer volume of enemies you deal with, vampire survivors often see the player moving away from whatever they're shooting. The end result is they're now moving AWAY from the money and have to jump into enemies and get harmed to collect it. While this can be seen as part of the challenge, it can also be really annoying to some. If you're going to make money despawn, I would say the base time should be a lot longer or that the default pick-up range is bigger (maybe even both) to make it easier for players to get their deserved rewards.
One thing I found myself wishing I could do was to organize the order of my weapons. You can do this when you have a spare weapon around, but it's time consuming and a little cumbersome. I'd love to see a way to organize one's weapons more easily.
Lastly, while some of the guns are really fun, others are just... dull. The Explosive Pistol. the Laser, the Grenade Launcher and the Faust all come to mind. The Faust would feel more fun if it was faster. The Grenade Launcher would be more fun if it had both more firing range and a bigger explosion radius. The Laser would be cooler if it could pass through enemies while firing, allow you to sweep through an army of enemies at once. Aaaaaand I got nothing for the Explosive Pistol. I just wasn't a fan of using it.
These were the main things I could think of bringing up. I hope they help you out!