Warp

There are 9 types of Kills in the game, and you need one of each. You do not need to do them in one playthrough, as they can in fact be done in the challenge rooms. It is marked as missable since one type (Fell) can only be done in the campaign, not in the challenge rooms as you might think.

The types are:
1. Frag: Standard kill, warp inside someone an kill them
2. Echo Frag: Warp inside someone, then swap with object/person
3. Friendly Fire: Person killed by guard or turret
4. Explosion: Use alien canister (the explosive one)
5. Alien Mine - The yellow, beeping mines that trigger when you walk over them.
6. Fell: Person falls to death
7. Crushed: Human crushed by object capable of crushing
8. Laser Beam: Human Killed by lasers
9. Water: Human drowns in pool of water.

Now, there are a couple places to do most of these, but for those interested, here are some of the places I got mine:
1. Frag: Pick a human, any human, and make him explode from the inside. Easily done
2. Echo Frag: Can be done right after getting the swap power. Warp into a scientist on either side of the chamber, and then echo swap to a canister or other human.
3. Friendly Fire: Use the Echo Challenge Room (#5). Immediately to your right, there is a section with four guards facing each other. Use an echo and place it in the center of the guards, at least one will be killed.
4. Explosion: Can be done right after the cut-scene where scientists explode one of these in the campaign. The next room with enemies will have these canisters. Warp in and out of one quickly, then head back to the entrance of the room and wait for the boom.
5. Alien Mine: Best done in the Launch Challenge Room (#7). The last three scientists, upon seeing you, will run over them. And you only wanted to say hi.
6. Fell: The missable one. Cannot be done in the Challenge Rooms, despite what you may think. I got this in the room where there is the cut-scene of the scientists killing the other alien creaturs (there are three grubs in the room afterward). The second chamber with a grub in it uses a trap-door. Use swap to trap a scientist in that chamber, hit the button on the floor directly outside it, and watch him fall.
7. Crushed: Again, use the Launch Challenge Room (#7). The first group of three scientists can be launched into the pit they are standing it front of, where they will be crushed.
8. Laser Beam: At the end of the Advanced Frag Challenge Room (#4), there will be two scientists (note, you can "complete" the challenge before reaching them if you destroy the turrets, so don't). When they see you, they will run away. Step on the button near them as they pass the wall on the right, lasers will shoot out and kill them.
9. Water: Shortly after getting the Echo power, there will be a hallway split into an upper and lower part that a guard with a half-shield patrols. There is water immediately to the right of his patrol route. Get in the canister closest to the water, and as the guard is between the canister and the water, explode the canister using Frag. If the guard does not end up in the water, you can push him in using your character as he lies on the ground.

Again, there may be other places to get these, just felt I should put down some locations for people looking to get them. Any questions or concerns, just leave a comment. Happy achievement hunting!

For this achievement, you must get every type of kill in the game.There are a total of 9 ways to get a kill. You will get most of these by playing regular. A good amount of these can be done in the challenges. Specifically, Challenge 7 has the Alien Mines at the end which you likely wouldn't normally obtain in the campaign.

1. Frag - Warp inside and kill someone
2. Echo Frag - Warp inside human, then echo to another human
3. Friendly Fire - Echo in between two guards so they shoot eachother
4. Explosion - Warp inside an alien canister or throw it at humans
5. Alien Mine - Best done on challenge 7, at the end the humans kill themselves on it
6. Fell - Toss a human over an edge
7. Crushed - Have a human get crushed something. Playing the later challenges gives this to you automatically.
8. Laser Beam - Throw a human into any lasers
9. Drowned - Toss a human into the water after knocking them out