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.
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.
Collect all the spooky Water Sprites.
Unlock all characters.
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 dying once (1-1 doesn't count!).
Beat a REAL level without getting hit (1-1 doesn't count!).