The story takes place on a fictional planet Sierra, where parasites called Scarlet have invaded the planet, they can live in humans, animals, even machines. Scarlet’s leader, Epsilon-Eagle, was ambushed and went missing, and Xi-Tiger replaced him, but he was quickly hated for being too cruel. Furious at that, Xi went to a lab and discovered Epsilon was inside a boy’s body and tried to kill him. Epsilon now transformed into a cyborg birdman and fought Xi; Epsilon’s personality changed from there; he felt his ugliness gradually diminished; instead of he became the right person and fought against the Scarlet army. The game is divided into 25 levels, along with the appearance of 31 powerful bosses. With side-scrolling run and gun gameplay, you will control Epsilon to fight against countless enemies. Epsilon can double jump and fly. Besides, he can also glide quickly to evade the enemy’s attack. The game has six different weapons, but you can only bring four types at once. You can also choose between two different difficulty levels, including “super-easy” and “superhard”.