Here is the full list of all 20 Clash Force achievements.
Kill 500 Enemies
Beat the game on Normal Difficulty
Leave the bonus level without getting anything.
Beat the first Level
Try every character
Beat the Game on Hard
Beat the game without dying once on the save file
Bounce on every mushroom in Stage 3
Reach the front of the mine train in Stage 5
Destroy every ceiling turret in Stage 7
Don't destroy any bombers in Stage 10
Destroy every bomber in Stage 13
Don't get hit by any mines in Stage 17
Get through a whole level without getting hurt
Beat 50 Levels
Beat a level without killing any enemies
Die 100 Times
Don't touch the rising lava in hard mode
Jump over the first totem pole in Stage 2
Complete the game on Expert Mode!