Here is the full list of all 15 Terry Poorflyer achievements.
Complete first level
Reach to last level
Collect all coins in the game
Stomp on a Crab
Stomp on a Scorpion
Stomp on a Bird
Collect water bottle
Jump into the abyss
You jumped on spikes!
Take a bath in lava
Listen to whole credits song
Stomp on a Frog
Collect BFC (Big Fine Coin)
Finish the game
Get damaged by King Crab