CRE patch
This makes the collectible items (Missiles, Super Missiles, Power Bombs, Energy Tanks) load their graphics to VRAM as-needed, as all other powerups in the game already do. It also allows you to place a large number of duplicate powerups in the same room, staying within the graphical limit of four different types of pickup per-room. This frees up some tilespace in the CRE (though it's not immediately present, as, I didn't force those graphics to blank-out in this patch).