EVOLVE 40 lvl achievement not unlock

this achievement is called APEX PREDATOR achieve level 40

Ok guys, I was lucky enough to find a match online last night and completed 'Blood on the Sand' achievement (just need to reach player level 50 now to unlock it)

Still looking to do;

Am I only Dreaming? (Reach Lvl 40 and complete waves 1-40 on Memorial Map)

Like Father, Like Gun (Reach Lvl 30 and complete waves 1-30 on Allfathers Garden Map)

If interested send a friend invite or message my way saying which you need.

Also how does lvl scaling work? If I am lvl 5 playing with a lvl 40 what lvl will the enemies be for each of us? Is it like Dead Island where the same enemy will be lvl 5 for me and lvl 40 for my coop partner, or is it like borderlands where the same enemy
will be lvl 40 rendering the lvl 5 character useless in battle?

Make that 2, now the play for 40 hours achievement wont unlock.

I didn't play much of the first 2 games and it unlocked for me right at the start. I only played enough Beta matches to get all the unlocks btw. Some people have said it unlocked around lvl 40, so you should only worry about it if hasn't unlocked by the
time you have Seriously 3.0.