Click to place a block, press 1 and 2 to switch between placing enemies and placing blocks mode, and press e to delete blocks. Press up arrow to change the size of enemies and blocks. Press down arrow to change the variation of blocks into their other forms. (Grass becomes dirt and slopes become stairs, and lava becomes lava triangles.) Last of all, press right and left arrow keys to switch between blocks. There is only one enemy currently. Press I to change into playing mode and editing mode and use arrow keys to move.
Just a test project to see how well it goes
