PixelDungeon Prayers is based upon Pixel Dungeon's Open Source code. It plays exactly the same as the original game with one exception. You can now pray to the Gods for additional powers and items.
From the original - Pixel Dungeon is a traditional roguelike game with pixel-art graphics and simple interface.
Explore the depths of Pixel Dungeon, collect useful items, fight fierce monsters to find Amulet of Yendor (surprise!) - the ultimate artifact of this game world.
"Roguelike is a sub-genre of role-playing video games, characterized by random level generation, tile-based graphics and permanent death."
Many people consider this game very difficult and luck-based. Anyway, you will die often. You are warned! :)
Note that PixelDungeon Prayers is a slightly easier version of the original. But you will still die. A lot!