It's a creative idea . Reminds me a lot of Ikaruga (a game where you can switch between light and dark "polarities" to absorb enemy fire).

I had trouble distinguishing the dark dimension from the light; would like to see more visual difference between the two.

I wanted to see the game lean further into the jam theme - true, you're not shooting in the light dimension, but you still are in the dark. I didn't feel a strong reason to have both. Would have been more interesting to embrace the light. There's this great level in the F-Zero GX single-player mode where you are racing other cars and have to destroy them to get energy so you can keep your boost going so you can catch up with the leader. The opponents become resources you have to use strategically. Something like that could work well here.

Interesting. It was fun to play

It's a very classic take on "your health is depleting" but I'd say it lacks a lot of polish and feeling on the gameplay