Contra Rebirth
Play as Plissken (lizard)
Successfully complete the game on the Normal difficulty to unlock Plissken (lizard).
Play as Tsugu-Min (robot)
Successfully complete the game on the Easy difficulty to unlock Tsugu-Min (robot).
Nightmare mode
Successfully complete the game on the Hard difficulty to unlock Nightmare difficulty. In Nightmare mode, any enemy that is destroyed will shoot a blue ring in your direction.
The image featured at the top of this post is ©The Legend of Heroes: Trails of Cold Steel III key art / Original