Here is the full list of all 38 Pitfall Planet achievements.
Complete the Factory.
Complete Greenwood Falls.
Throw your friend off within 10 seconds of starting a level.
Complete Sewage Treatment.
Buy your first hat.
Complete the Outpost.
Complete the Tutorial Caves.
Complete every level in Pitfall Planet.
Collect every gem in Pitfall Planet.
Buy 5 hats.
You've bought all the hats!
Collect all the gems in the Tutorial Caves.
Collect all the gems in the Outpost.
Complete the Chimney.
Collect all the gems in the Chimney.
Collect all the gems in Sewage Treatment.
Collect all the gems in Greenwood Falls.
Collect all the gems in the Factory.
Complete the Dead Caverns.
Collect all the gems in the Dead Caverns.
Complete the Mountainside.
Collect all the gems in the Mountainside.
Complete the Dead Desert.
Collect all the gems in the Dead Desert.
Complete the Rose Caverns.
Collect all the gems in the Rose Caverns.
Complete the Old Watchtower.
Collect all the gems in the Old Watchtower.
Complete the Mountain Core.
Collect all the gems in the Mountain Core.
Find the hidden gem cave.
Find the frozen miner.
Find the secret arcade.
Complete the game while always getting both players into the elevator.
Seriously, what's up with that?
Beat the race challenge in 30 seconds.
Reunite all the missing astrobots.
Find Kate's launchpad and her final diary entry.