You say the cube itself didn't load? The cube is hard-coded as a loading screen, so if it wasn't showing that then it must have failed to initialize either WebGL or WASM. If you're willing to try again, hit F12 before clicking "Run" on the game, and paste any console output here, as well as what browser you're using (I already found out from someone else that apparently Firefox doesn't support OpenGL line drawing, so the test levels don't even show up, whoops!). Can't update for the jam entry of course, but I plan to keep working on the engine so it would be really helpful feedback :)