Online achievements confirmed! They can be unlocked in a private match!
"Crushed!" obviously has to be done in 'Frag Chamber'. You can also do "Ninja Killer" on that map as well. Every time you close the chamber and it reopens, an Invisibility power up appears. Just repeat however many times as needed. The Invisibility only lasts a minute of so, so if your partner is quick, you can get maybe two kills from one power up. Just keep closing the chamber for more to appear.
"2 Deaths - 1 Gun" has to be done with a minimum of three people and you have to kill both players with one rocket. There is a rocket launcher on 'Frag Chamber' (its in the wide blue-walled room at the bottom of the stairs near the chamber). Pick it up and have the two other players stand in a corner or something (as the rocket has a tendency to push them back) and fire away. You might want to have each of them shoot a couple of bullets into each other to weaken them, because I found that one rocket doesn't necessarily kill you.
"Telefragged!" and "Berserked!" can both be unlocked on 'The Edge 2'. To get "Telefragged!", have one player go through the teleporter and then another player follow them through. No need to actually kill the person as going through the teleporter after them kills them. There is also a Berserk power up at the other end of the teleporter, so just wait there until your boosting partner shows up in that room again, pick up the power up, and punch them dead. Be warned, it takes about two minutes or so for the power up to reappear, so be prepared to wait.
"Clean Sheet" can be done on any map obviously.
Remember, you can change the time and frag limit accordingly to get these done.
Whew! Glad they were easy! This can literally take just two matches (one on 'Frag Chamber' and one on 'The Edge 2') with an unlimited time and frag limit. Just keep trading off. I think these took my partner and me about 30-40 minutes, and we had a couple of false starts because we were looking at what maps were best to do these on. So if you have three people, maybe an hour for everyone to get all six achievements.
BTW, I still need "2 Deaths - 1 Gun", so if anyone wants to help out, it'll literally take minutes. Send me a message on Live. I'm on now and will be for the next couple of hours (currently 10:40pm EST on Tuesday). I will help anyone who helps me!
EDIT - Got the last online achievement. Thanks Skaidtheking and CurseofSamhain!
Last edited by bLaKgRaVy; 10-17-2012 at 03:51 AM.