I've won 4 Long games on amusement park on normal so far and still haven't got the flea market achievement. How many must I win?
OR.........find a crappy teamNormal can be fun, you've just got to limit your weapons a bit. Like don't pick any tier 3 weapons. It makes life more interesting. And go the perk you use least, just to spice things up even more. There are ways to do it, but yeah, i'm not a big fan of playing the normal ones either...
For some reason, I haven't been able to get the Survive 10 second's after a Siren's scream on Hard or above, Tier 2 weapons and Kill a Husk with a LAW.
This appears to be a fault on our end. There is a code error that's causing the game to believe your friend already has those Achievements, even though he doesn't. The Achievements will unlock for him just fine in Solo mode or he can wait for us to fix it for multiplayer(we're not yet sure when it will be fixed, though).