Enchanting
The higher levels they reach, the more orcs they find.
On level 10, they encountered 200 orcs in total. But by level 20, they have to clear close to 500 orcs to advance to the next level.
Not only that, the orcs no longer came in waves of 20, but they have increased to 30 or 40 at a time. Occasionally, two groups would charge at the same time, causing them to have to take a defensive approach.
While they have to deal with the sudden escalation, they still have other things to deal with. At the end of level 20, a new group of orcs emerged from the shadows, followed by the footsteps of misshapen creatures. The growling and shouting they did made a lot of commotion.
Thud! thud! thud!
They certainly look similar to the usual orcs, but instead of green skin, these creatures have mottled gray skin that looked like stone, and their muscles were much bigger than their counterparts.