I originally heard this referred to as Risk of Rain 2 meets Borderlands, and honestly that kind of fits. You have a large cast characters that all play very differently with their own unique powers and talent trees, as well as a buttload of guns/weapons which themselves can come with a near infinite assortment of inscriptions to modify their behavior.

The game has come a long way from where it started, and with the new DLC it is solidly a 10/10 game for me. It's a blast in both single player and Co-op. The Reincarnation difficulties drastically change up the game too, so end game content on this game is incredibly fun and doesn't get stale. The spiritual Link option is especially fun since it lets you synergize scrolls and abilities.

This game has risen the ranks to become one of my favorite games overall. I Strongly recommend it.