really cool project! saw Deynum Studio's video and had to take a look myself. Risk of Rain 2 is one of my favourite games and I can see you've taken inspiration in some parts (i think?) which is awesome!
Different enemies would be an improvement. I think the enemies should also be a different colour, such as purple, to make them stand out from the background more. The swarm queen was a great boss and I think the enemies would benefit from a bit more narrative, to explain why they are there. (in RoR2 the enemies are different species of alien rescued from dying planets, and there are boss versions of each individual enemy).
All that said this is a great underrated project and I hope you continue working on it!