I got my backer key on Friday, so I played about an hour of Knights & Bikes today. So far, it's pretty good! The art direction is totally charming, and story is very whimsical(with something dark lurking beneath it), and the gameplay is simple, though fun. It really reminds me of Costume Quest in a way, but without the turn-based RPG combat. You follow a linear map(with secrets), collecting stuff, killing enemies, and unlocking areas as you go.
You can play with a friend either online or local co-op, but I've only tried it solo, and you can swap between the two characters. Demelza is the redheaded kid, and she is a melee fighter, while Nessa used a frisbee for ranged attacks. There are basic puzzles(hitting targets within in a time limit, hitting targets in a certain order), as well as enemies to fight. At some point you unlock a bike, but I haven't gotten that far.
The story is cute. Demelza is being raised by her dad(a former roadie) who built and runs a medieval--themed golf course/caravan park on an island, that is struggling to stay in business. The park's theme is based around a local legend about a group of knights who buried some treasure on the island, and there's a curse? I dunno. It's cute. Anyway, Nessa shows up on the ferry with a load of supplies, and seems to be homeless. She befriends Demelza, and they team up to search for the treasure.