Player Mode: WASD/Arrow Keys: Move and jump 0: Enter Builder Mode Builder Mode: WASD/Arrow Keys: Fly Click: Place Tile 0: Enter Player Mode Keys 1-4: select tile type (press repeatedly for more blocks of the same category) E: Eyedropper Tool (Hover over tile to select) R: Reset Level and input level dimensions L: Choose Level
Thanks to Griffpatch for the guides!