Really solid game. I love how you've handled the duality of the red and blue worlds. Every time I reached a dead end and switched to the "other world" and discovered a path forward it felt like I found a secret. The path to the early blue button felt like four or five secret finding accomplishments in a row. Really hit my dopamine.
I found the controls unintuitive and ended up using both the arrow keys and W to get around. I'm glad you added looking up and down but if I could have done all the movement and looking navigation with on hand I didn't figure out how.
Having the combat be a "get the cursor to the targets without getting hit" slow-mo bullet hell was a nice twist. I like it a lot although consistently I found it really easy.