The Tower of Zeldaga is a free retro mash-up of Zelda and Druaga in which you rescue Ganondorf from an evil blonde queen

The Tower of Zeldaga is a free browser-based retro mash-up from Osmose that blends NES-era Zelda with Namco's 60-floor maze RPG The Tower of Druaga. In it, Prince Ganondorf has been abducted by the evil queen Zeldaga, and each room hides a secret, with some pitch black. The developer says the hardest puzzle may require datamining to solve.