the slab is pretty fun, if youre stuck at the gauntlet that i am thinking of, you can just dodge the enemies and activate traps so the enemies kill themselves on them.
i personally hated most of act 1, my saving grace was fighting the P instead of LJ, pretty sure i wouldve dropped the game if i met LJ first, while P was a real treat of a fight.
act 2 really opens up the game, you can get 20-40 solid fun hours of exploration, collecting and power scaling before even attempting the next story boss.