Here is the full list of all 10 Mutant Mudds Deluxe achievements. It takes around 8-10 hours to unlock all of the achievements on Windows.
Collect all the spooky Water Sprites.
Collect 4000 Golden Diamonds, unnecessarily.
Unlock the path to space.
Beat a REAL level without using the checkpoint (1-1 doesn't count!).
Beat a REAL level without getting hit (1-1 doesn't count!).
Beat a REAL level without dying once (1-1 doesn't count!).
Beat the game. You'll know it when you see it.
Collect all 'known' Water Sprites and Golden Diamonds.
Collect all of Grannie's medals.
Unlock all characters.