http://www.gamefaqs.com/pc/370861-deep-fighter
Deep Fighter. Really awesome submarine-based FPS game. Combat and controls are really fun, you get new ships as the game goes on that drastically change gameplay, and there are plenty of clever physics and "platforming" puzzles. I dunno how obscure it is, but it's probably my most obscure favorite game.
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_foolmo_
'but that statement is something only an Aspergers patient would say' - UltimaterializerX