Solutions for problem achievements.
You can always use ‘Steam Achievement Manager’ to cheat these if you don’t feel bothered. I have provided solutions to doing things if you don’t have any friends.
Most stuff you will get through normal gameplay.
[Change in Command]
You can ask an admin to set your role to D-Class and theirs to MTF. Get to the surface as a D boy with a gun, but don’t escape. Run to the MTF spawn and face a wall so spectators don’t know where you are. Wait for the spawn, you’ll hear a helicopter, and wait another 10 seconds for all the MTF to run by. Walk up to an AFK member and hold E. Achievement done.
[Be Polite. Be Efficient.]
Join a server with 40 players.
Suicide quickly at the beginning of a round and wait to spawn as MTF/Chaos. Whichever you spawn as, run to the spawn of the opposite team and face a wall. You’re hoping that enough sci/d-boys/guards survived to warrant the opposite team spawning.
It really helps to have a large magazine capacity and a grenade for this achievement. You’ll need to hit headshots. Wait for the spawn, don’t move until you hear boots moving. Most servers have 5 seconds of spawn invulnerability, but it’s useful to find ones that don’t. If there is spawn protection, wait 10 seconds and kill the AFKs. If there isn’t, kill them.
Join a server where friendly fire is on. Have a teammate shoot you in the foot one at a time, pop SCP 500 beneath 10HP. It might be higher, but I got the achievement at 8 health.
Obtain Micro H.I.D, charge it or fire it until it’s empty. While holding it out, jump in to a tesla gate.
For the grenade achievement, I’m pretty sure I got it when I threw a grenade in to an elevator full of friendlies. It might be worth testing whether you can get [Be Polite. Be Efficient.] on a server you don’t care about in the same way.
The seasonal achievements are locked and cannot be obtained through the Steam Achievement Manager cheat tool, but the rest can.
For [My Cure is Most Effective…], I believe reviving dead zombies counts towards the score, I don’t believe you need new infections.
For [Anomalously Efficient], you’ll need to kill a guard. Don’t bother trying to get to light on time.
[High on the Wings of Caffeine] and [Property of the Chaos Insurgency] can be done in tandem on a very low pop. server.
[That was… close.] is pretty easy, just camp nuke room. Please note, it can not be turned off below 10 seconds.
[Is This Thing On?] can be done without a mic, so long as you press your push-to-talk button at the machine. You can set your steam mic up to capture desktop audio, it only needs to play a millisecond of white noise and you get it.