This is not recommended as I plan to rewrite loads and loads of stuff that is quite important to the level design. It is probably one of the parts of the game that is closest to its original state, which you can tell by looking at the really really hideous code.
To add new levels, you must enter the dangerous world of the level designer. The level designer is run by typing
hatman -l <level-file>
And selecting the level editor option from the menu. This will bring up a picture of the level, (or a blank level if the file you named doesn't exist already) and a menu of the blocks along the right-hand side. Use the following keys to create your level:
Slides the blocks up and down on the left.
Puts the top-most block into the white box.
Tries to automatically line up the walls.
Saves your level.
Lets you test your level.
But level design isn't all fun and games, oh no. There are rules, goddammit.
So long as you follow those rules, your levels will always work. But there are other considerations...
When you've finished, press s to save your level, and q to quit the editor. Or, if you are feeling fairly bold, press t to test your level. Actually, I think I deleted the code to do that. We're sure you'll get the hang of it eventually. If you need some help, check out our levels (not all of them work currently), or feel free to e-mail us.
Another important unit in Hatman is the ``game''. A game consists of a file, with a list of levels and lots of numbers and stuff in. Take a look at the example hatman.game for more information - but be aware this file is going to change somewhat in a future release.
The sprite editor has taken a bit of a break. Erm, maybe I'll write a new one some time, but right now it's not there. Sorry.