Not the average dungeon crawler or legacy game. Gloomhaven is similar to playing a predesigned D&D module without the need for a DM. Gameplay is strategic and challenging. Players build a hand of cards for their movement and attacks. These cards need to last long enough to complete a dungeon. Powerful attacks deplete the characters quickly as they can only be performed once and reduce the hand size. D20 Dice have been replaced with a deck of cards that can be customized as the characters level. Character eventually meet their life goal and retire unlocking new character classes to continue this epic adventure. 17 unique classes,a world that levels with you, branching story, 90+ predesigned locations to explore and a random dungeon generator, it very impressive.
FYI - Retail is identical to the 2nd edition kickstarter edition and the 17 solo scenarios were freely released by the developer online.
I would recommend a storage solution, what is included is ok but setup and takedown is very time consuming.