Well, actually you can play but... the single most defining feature of the game, the double jump, mostly doesn't work. Did you really test this game with 1.9 before upgrading? I've played three games and even managed to win one and be second in the other two, but the overall experience was truly painful :-( It's difficult to add some helpful information, the double jump seems to stall specially when tried over smooth surfaces like wool, but not only. Oh, and the scoreboard has also run crazy. Dead players still appear with one life. I'd like to say I hope that my favourite Minecraft game will be back soon. But I really don't. You have stated that 1.8 is history and I doubt very much you can fix the problem quickly, judging from the pending superflat bug and the many months that Assasination was broken. Or can you?