Well, I have the basics of the level editor done. Saving/Loading levels of different sizes, opening different tile sets, and drawing the tiles to the map. Here is a screenshot of the level editor, as of right now, along with Caliber9's sweet looking cave tile set:
Next I have to add in the actual tile types for each slope. Then I'll have to add in support for adding in enemies, powerups, triggers, and those kinds of things. Keep checking for updates.