We apologise for the delayed feedback:
So right off the bat I want to say amazing work on the Main Menu UI. I can tell that you put a lot of time and effort into making it look nice and feel nice. It was super easy to use too. A suggestion for the Main Menu UI though is allow Left click to work as E did. I clicked so many times before realizing that I had to use E to select anything. Also when changing any settings, I don't know if this is an HTML thing or not, if you return to main menu it resets all settings back to default.
Now onto the overall gameplay. The guns felt really good and felt like what they should be based on the weapon. Having drop off on a grenade launcher is something I did not expect nor did I expect a grenade launcher to be part of the kit. Once I got the hang of W for jump and Space for dash I got into a really nice groove. This all came crashing down though once I hit the Robot green eyeball monster. I could not figure out if I had to kill it or if I had to solve something to exit the doors. There was no HP bar or indicator on if it was dieing though. I eventually died and was not able to move on from that point. The music was really good and kept me feeling like at any moment I would be fighting a ton of enemies so it kept me on my toes. Even though you said you aren't good at pixel art in your GDD you did a great job and gave the game a great vibe. I can't wait to see this game with some polish and new features.