Reach for the Sky: With a railgun (or other long-range weapon) go to the Crash Landing map and jump from the utter left jump pad. don't press any direction during your flight. when you land , go right a bit and shoot the white glowing moon partially behind the planet with a sniper. Reward: Moon Corpses Mode.
I Hate Nature: With any weapon (I recommend the Laser Minigun), go to the facility/lab map and get to the plants hanging overhead on the ceiling. Shoot until... Reward: Unlimited ammo mode. (Tip: Due to the Laser Minigun quickfire speed, it can make many shots in a minute, and you can get that achievement in 30 seconds) reward: Unlimited ammo mode
Love is Blind: Do the first level on the Human Campaign. Before the missile comes down, go back to the place where you started and walk into the giant heart to get the medal. Reward: 4x health mode.
Oh Hi Kitty: Go to the Frostbite map and go to the big iceberg at the very top. (It is nearly impossible to get there.) Once you are up there, go to the middle and jump. (The map drains your health so be quick!) Reward: lol cats mode.
To activate the modes, select the special mode option and chose the mode that will be enabled during quick match. However, for most modes they will subtract -20, -40, -50 -60, -90, and even -100 credits from your overall credit total.
If I see more comment and more edit to this wiki I will tell you a new class!!!!!!!