Good stuff! Nice sound effects. The enemies look great--using the particle system was a really effective hack. Well-designed levels. Overall, the game is challenging without being frustrating.
The atmosphere is effective. I'd say the white platform blocks in the earlier parts of the game detract somewhat from the darkness, but perhaps this is intentional (because this is in the earlier parts of the game).
Also, the main character appears to jiggle a bit when moving; I'm not sure whether that is due to some issue with configuring the camera (I know nothing about Godot at all!).
(Coincidentally, I recently did a space platformer myself for a 3-day jam. :) )