The Binding of Isaac

Summary pulled directly from Steam - Some text may only be applicable to Steam platform

When Isaac’s mother starts hearing the voice of God demanding a sacrifice be made to prove her faith, Isaac escapes into the basement facing droves of deranged enemies, lost brothers and sisters, his fears, and eventually his mother.
The Binding of Isaac is a randomly generated action RPG shooter with heavy Rogue-like elements. Following Isaac on his journey players will find bizarre treasures that change Isaac’s form giving him super human abilities and enabling him to fight off droves of mysterious creatures, discover secrets and fight his way to safety.

Key features:

Randomly generated dungeons, items enemies and bosses, you never play the same game twice.
Over 100 unique items that not only give you powers but visually change your character.
50+ enemy types each with the ability to become "special" making them extra deadly but they also drop better loot.
Over 20 bosses.
4 full chapters spanning 8 levels
3+ unlockable classes
Multiple endings
Tons of unlockable items, enemies, bosses and more.