Subbania: underwater action-adventure about Nazis and their attempt to escape from hell. With a minimum of four different weapons, 118 areas, and 60 enemy types (and not just some half-assed palette swaps), there's loads of content.
Additionally, it features a
very simple binary lighting system vector-based lighting system.
Subbania's been released -- here's a link to a playable version and here's a link to the Chrome Store version.
Blog article here.