In Red Faction: Armageddon, I played Infestation coop and resumed later, the difficulty seemed to have dropped, why?

Question

A friend and I played up to wave 10 on normal difficulty. By the time we'd hit wave 10, there were monsters everywhere and it was total chaos. We were having a great time.

We continued playing today on wave 11, normal difficulty (this was pre-selected on the lobby screen) and for some reason it was a complete joke, there were barely any monsters and it wasn't fun at all.

Any idea why the difficulty just completely went to zero after restarting?

Answer 1

The difficulty peaks every 10 waves, dips a bit, then gradually builds back up and peaks even higher 10 waves after. To use an example, wave 11 will be easier than wave 10, and 21 easier than 20, though 21 will still be more difficult than 10. The hardest wave, obviously, is wave 30.