Retro characters -  each inspired by classic 80's or 90's games.

In-game editor & Workshop support -  Create characters, levels, tilesets, etc., and share them on Steam Workshop.

Adventure Mode -  The plan is to add a campaign with levels from each of the character's worlds. Currently there's only 2 default adventure levels but you can get more from the Workshop.

Battle Mode - One-life rounds with a focus on items.   Each character gets their own items/upgrades from the item spawn points. Characters can even have different item spawn rates, so weaker characters can trigger item spawns more rapidly, and vice-versa. Also, in 3 or 4 player free-for-all battles there's rubber-banding: the losing player can get more items/better items with the opposite for the winning player.

Play online with Steam's Remote Play Together , or locally on the couch with friends.

Full gamepad support - I play the game with my old NES & SNES controllers from my childhood (via USB adaptor).