Gap between level and skill

Tom's small group blasted through the levels as if there was no tomorrow. Even though neither of them received any level-ups ever since reaching the sixtieth floor, they still managed to somehow keep up with the rising difficulty of the dungeon.

The main reason was pretty obvious and had a shape of a human working with a spear. 

With Tom thinning the herd of every floor and allowing only a few monsters to reach the rest of his group, they could still keep up with the pace while dutifully practicing their skills and cooperation. 

Yes, cooperation. 

This was the biggest element of Tom's plan of defeating the last boss. Because even if every single last one of them reached a hundredth level or even higher, Tom still doubted that they could tackle the last boss on their own. 

'Well, it goes without saying. I never defeated that dragon girl once,' he thought, the taste of those previous defeats still souring his mood.