Hey, thanks a lot! The ship's movement is something I'm not super satisfied with either - I didn't want to make a dual stick shooter but instead make this a more proper luolalentely game - and with that, especially the rotation of the ship at times feels awkward as you collide with walls and might not be able to turn. I might still rework this a bit.
The web version has its flaws, but I still prefer to have it, as it's so much easier to launch and test. I'm developing on a Mac and rarely boot up my PC, no wonder there's bugs in the standalone version too... Although, I did put a, I think, standard "get_tree().quit()" there, which I thought would quit the game just fine, but I'll have to take a look at what's causing the crash, thanks much for reporting!