This threw an error for me looking for a .NET assemblies directory (usually happens if you're using the C# godot build) that probably should have been uploaded along with the exe as a zip file. The game still seemed to load up and I didn't see any .cs files in your repository, so this might have been buildable using the base version of godot (without .NET support) so that you wouldn't need those and/or could avoid that error.
You've got player navigation, health, obstacles and hazards, which is a good start for a first game! I found the black hole gravity a little punishing....if I was close enough for it to start pulling it was impossible for me to escape anyways, which made the heal stations a bit moot.
For the level design woes you mentioned on your page, a tilemap would be a great way to go for this kind of top-down game, and would avoid some of the little weird collision hitches that happen at some of the narrow passageways. They also make level design much faster, since you can essentially 'paint' with your various pieces instead of needing to do each part of the level in a bespoke fashion.