Space Barnacle

Here's a fun little retro game (although it only plays in a window, ooo I hate that)
to quote from here "I wanted the game to feel like a long-lost budget title, perhaps developed for the NES or Commodore 64 somewhere between 1989 and 1990."

And it has "additive blending, parallax scrolling, and particle effects for blood and vomit explosion"

hot!
Not to mention taut philisophical dialogue