HamSwap

Quoth HamSwap's readme:

 HamSwap
 by SpaceManiac

 HamSwap is a tool for backing up your Loonyland and Kid Mystic world
 files and copying over custom world files to the ones the game uses. 
 Just copy and paste hamswap.exe into either your Kid Mystic folder or
 your Loonyland folder (same one mystic.exe or loony.exe is in). Before
 you run it for the first time, make sure all your world files are at
 their original so HamSwap can make backups. You can then restore the
 backups from within HamSwap at any time.
 
 The file naming system HamSwap uses is simple. For Kid Mystic, world
 files are simply named with a .dlw extension. For Loonyland, world files
 are named with one of an .adv.llw, .boss.llw, .ball.llw, .survive.llw,
 or .bowl.llw extension depending on what type of world it is. This is to
 avoid confusion as to what type of world they are.
 
 Included with HamSwap are some example addons. Thanks to Davedude for
 contributing example.dlw for Kid Mystic, a quick adventure with a few
 easy levels. For Loonyland, there's example.bowl.llw which I made, and
 example.boss.llw by Redbone (thanks!). These are placed in the Kid Mystic
 or Loonyland folder the first time you run HamSwap, and can also be found
 in the hamswap.vfs folder.

 For those who are interested, this program was written in Tcl using the Tk
 library for the windows you see. Full source code is available in the
 hamswap.vfs folder, if you care to know how I wrote it. If HamSwap isn't
 able to detect whether you're using Kid Mystic or Loonyland (which it should,
 if you put it in the right place), pass it "km" or "ll" as a command line
 argument.

 Thanks for using HamSwap, and enjoy!
     - SpaceManiac

Download!