99 Levels to Hell is a platform shooter with lots of guns, upgrades, magic, traps and monsters to kill. It's is a rogue-like, which means surviving is key and every time you play you get a new set of levels to play. When you complete 10 levels, the 10th being a boss-fight you unlock a door to the next dungeon.
Hidden in the darkness of the dungeons are shops, casinos and elevators. And if you search the dungeons carefully, you might find secret rooms that unlock more of the story, and free new adventurers, you can play as in your next game.