I'm one major boss in and I'm having a blast. The gunplay is tight and the movement is amazing. Each character has a very different movement style that changes the way you play. The writing has me busting my guts and the game is gorgeous to look at. I can't wait to see the continued support they've already been talking about and showing off.
EDIT: I've put a decent amount of time in this game now. While I am enjoying the gameplay that is there, I'm pretty disappointed that there wasn't more story, or even just more "story quests" to lay down some more story and show of the voice acting I am so fond of. Joker is fun to play, all of the movement feels great, the weapons work, but there just isn't much to do yet. Wait for a sale and I hope they figure it out and give us more actual stuff.