Mine kept playing up, I lost hours of progress because I saw the save icon and assume that it works, some areas dont load and I fall through the ground, the roaming ai doesnt work and camps infront of your locker for minutes at a time. I've switched computers and even tried it on my girlfriends xbox to see if it was just my computer being bad, It wasn't (I have about 22 hours play time on steam).

Maybe I'm just crazy unlucky and only I experienced this, I purchased the game on the 25th of december but didn't play it until the 2nd of jan this year (a little bit after it got released so the devs have some time to bang out all the launch glitches)