-Press 1 for a mover cell, press 2 for an immovable block, press e to select nothing, press r to rotate the mover cell. -If you select a mover cell and hover it over the immovable block, it will delete it. It also works the other way around. Also, don't put a ton of blocks down, it will get laggy sometimes! -This could also be considered multiplayer in my opinion because you could make levels for others to try.
-Huge credit to Sam Hogan for the idea! (For those who have no idea who Sam Hogan is, he is a popular game programmer on Youtube) -Thanks to Griffpatch, I can now snap grid cells! -Sound effects from Undertale. -This is a test for grid snapping in future games.