Recs.
Updated
The Binding of Isaac is a Legend of Zelda-inspired game where Isaac is trying to escape from his own mother, who is trying to kill him because she heard a voice from God. It has heavy roguelike elements.
SpecsUpdate
Pros
Pro A high amount of content
The Binding of Isaac is one of the best roguelikes out there. It's difficult to beat completely, but immensely satisfying when you do. It has gazillions of unlocks, secrets, bosses, power-ups and item combinations. There's also limited co-op (BoIR only). The game can be genuinely terrifying and dark, especially if you take a moment to ponder what's really going on with its backstory and characters.
Pro Powerups combine in very unique ways
There are tons of unique power ups, and most of them interact with each other to create really interesting combinations. The main attack in the game is shooting a projectile, and modifiers stack on top of that, which makes for some really unique attacks. For example, you can have a homing, multi, laser attack that shoots in both directions by combining multiple treasures. You can build interesting strategies this way, which keeps the game feeling fresh.
Cons
Con Co-op feels like an afterthought
The second player can control only a much weaker version of the character and is completely dependent on player 1.