Here is the full list of all 8 Way of the Red achievements.
You like money.
You've defeated mutant zero, the eldest son of the king.
You've defeated 100 of the most numerous opponent! Never let a bird get away!
You've found every hidden seed! Congratulations!
You ate every red seed you found, and became the new ruler.
You beat the game, the straight-edge way.
You've become the master of combat!
Wow! You beat the game without learning any extra abilities! Incredible!