The Ooze

The Ooze is a Sega Genesis game in which the player assumes the role of a scientist named Dr. Caine. After he discovers a plot by his employers to release a deadly plague onto the world and make millions of dollars from the antidote, they capture him. They inject toxic waste directly into his veins, causing him to dissolve into a green ooze which sinks down the drain. He wakes up as a sentient puddle of glowing green ooze with a human head in the middle and an extendable arm. Understandably angry, Dr. Caine seeks revenge against his employers and plans to stop them before they release the plague.

Tropes used in The Ooze include:

And I Must Scream: The game over screen has you trapped forever inside a lava lamp. Considering that you're a sentient puddle and can not die through natural causes... The bad ending also has shades of this, with you unable to turn back into a human.
Body Horror: Caine himself, as well as some of the monsters he fights.
Cast From HP: Your projectile attack uses up a small piece of your body with each shot.
Fridge Horror: When you think about it, slowly dissolving into a pile of slime while conscious would be insanely painful.
Multiple Endings: Although they're not that much different from each other.
Name of Cain: the name of the protagonist is, well, Cain.
Nintendo Hard: Despite being a Sega game, this game is near impossible to just beat, let alone get the good ending.
One-Hit-Point Wonder: If anything hits your head even once, you're donezos.
Weaksauce Weakness: Your body disperses easily, and you can die by being sucked into drains or rolling downhill into a body of liquid.