Also, try using a bit of LUA
-> Download 'Playground' (unheadered) <-
Release date: December 19, 2007
I couldn't contain myself to 1 room, so I went with 1 large room, a boss, and 2 smaller rooms. I know that some of the items look like other items (like the mysterious chargeball, or the even creepier springsuit...), but just pay attention to what the item actually is.