This mod strips down Spelunky to the bare minimun number of levels needed for it to function. It's also portable. (Yay Moloch!) But you can't have it in the same game folder as Portable Spelunky, because I'm lazy and didn't change the filenames.
Features:
Seven Levels of Spelunky, perfect for short breaks.
-One Cave
-Two Jungle
-One Dark
-Three Temple, including boss.
Adjustments for reduced game size:
-Every bonus room requirement has been halfed.
-The Ankh now costs $20000.
-A Super Crate spawns in the first level of each area.
-Key and Locked Chest always spawn on first level.
-Black Market entrace is always on the second level.
-Moia Head always spawns on the fourth level.
-Sceptre and City of Gold Entrance spawn on the same level.
So give it a try!