Completion bonuses
Successfully complete the game with a "B", "C", or "D" rank to unlock the Leech Hunter mini-game. Successfully complete the game with a time between 3:31 and 5:00 for an "A" rank to unlock the Submachine Gun and Leech Hunter mini-game. Successfully complete the game with a time of 3:30 or faster for an "S" rank to unlock the Rocket Launcher, Submachine gun, and Leech Hunter mini-game. Note: To get a rank after completing the game it must be played on the normal difficulty setting. You will not get ranked on the easy difficulty setting, but can still unlock the Leech Hunter mini-game.