Here is the full list of all 15 Lil Splody: Look Out Below! achievements.
Defeat CloudBurst in battle.
Defeat Big Brick in battle.
Defeat Avalanche in battle.
Defeat King Pin in battle.
Defeat Zodac in battle.
Unlock one bombling.
Unlock three bomblings.
Unlock all bomblings.
Completely fill the battle meter without being hurt.
Complete the tutorial.
Die with no more than 30 points.
When starting a game, don't move until you've reached 750 points.
Reach 15000 in a single game.
Defeat all bosses with each bombling.
Finish all other achievements.