Make sure you're picking up all items as they drop, and hopefully you get lucky on item drops in the first place. 2 more levels is definitely doable. I agree that the time may a tiny bit too strict though. A guy in my chat's game runs slow, he can't even come close to beating it.

Have you been manually advancing too when stage is cleared?

Also although campaign clock is obviously bugged, you got to 140 in 1h 15 min so it doesn't seem like you can finish 150 by 80 mins.

Maybe try borrowing other people's laptop/desktop?

Also, don't open any chests while doing the speed run. While you open a chest, the game pauses but the timer doesn't.

are you setting the game to low quality?
it stops the items flying to the quest area animation, so the quests take a couple of seconds less to register as finished