While the Mystery Dungeon franchise has been around since 1993; I imagine a lot of players only got their first taste of it more than a decade later when developer Chunsoft teamed up with The Pokémon Company to make Pokémon Mystery Dungeon: Red Rescue Team and Blue Rescue Team for the Game Boy Advance and Nintendo DS respectively.
Unlike most Pokémon spin-offs, this one has survived through amazing highs — Explorers of Sky and Super Mystery Dungeon — and some unfortunate lows — Gates to Infinity. Rescue Team DX brings it all back to those first two games with a fantastic new art direction and improvements to the classic formula that modernize the experience, if only just a bit.
Source: Destructoid Review: Pokemon Mystery Dungeon: Rescue Team DX