1. I disagree about limiting achievements to "trusted servers". I understand where you're coming from, but ultimately players who really want to cheat will find a way to cheat. In fact, there is a "Steam Achievement Manager" that allows you to give yourself any achievement at a click of a button, and you can't do anything about it because it completely bypasses any measures you have in-game. In short - cheaters gonna cheat.
Limiting achievements to "trusted servers" will mainly affect honest players and server owners - it would discourage server owners from hosting scripts that would make their server "untrusted", and would discourage players from playing on such servers because their progress toward achievements won't count. This would also require an extra level of control and anti-cheat measures that you'd have to put effort into.
I think the opposite should be done - add some ridiculous achievements that are impossible to get during normal gameplay (like getting maximum possible kill streak, whatever the text for it is), and encourage players to experiment with single-player weapon-mods, or play on modded servers and custom gamemodes (like Zombie servers).
Achievement progress should not count when killing bots, or when you're using a modded weapon. But besides that I think there should be no limits.
2. Please don't reward and encourage hacking, spawnkilling, etc. by adding achievements for it. Don't know if some people here are suggesting it as a joke, but I'd think it's obvious why it's a bad idea.
Achievements should act as a way to teach new players basic tricks and meta of the game, provide challenges for more experienced players, encourage players to mess with the game and explore modding and community content, as well as just random little things for cheap satisfaction. Personally, I'd rather not see something boring and ridiculously grindy like 100000 M79 kills. I'd keep it at 1000 maximum for primaries, and 200 for secondaries. Something you can reasonably achieve within 10 hours of gameplay using the same weapon, and get all achievements by the time you clock in about 150 hours.
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- There's no "sprint" button?!?!
Reach speeds of [X] by hopping (running and jumping at the same time).
* (replace [X] with the average speed at which players usually move by running and jumping). There could be additional achievements, each with higher speed requirement to get players to master basic movement.
- Rocket
Stay airborne for 5 seconds.
- Helicopter
Stay airborne for 10 seconds.
- UFO
Stay airborne for 15 seconds.
- Is that a Bird?
Fly like Superman. Jet while prone for 3 seconds.
- Phys-Ed
Perform 40 backflips in a single match.
- Olympics
Hop, perform a backflip, and fly like a superman while maintaining a speed of at least [X].
- Floor is Lava
Get hurt or killed by floor.
- What goes up must go down
Kill yourself with M79, LAW or Knife after projectile has been airborne for 3 seconds or longer.
- Advanced ballistics
Do [X] damage to players with ricochets.
- Second-hand
Kill 2 players with two different secondary weapons without dying.
- Is This Yours?
Kill a player with their own knife.
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Bonus kit achievements
- Anger Management
Kill 5 players without dying while in Berserker mode.
- Spec-Ops
Steal a flag, return a flag, or kill a flag carrier while in Predator mode.
- God is tired of your sh*t
Set 20 players on fire.
- Life Jacket
Take [X] amount of damage without dying while wearing Bulletproof Vest.
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Specific weapon achievements. These achievements should give new players a hint on how a weapon should be used, as well as provide some challenges for more experienced players to complete. Some ideas:
- Two Shots, One Kill
Kill a player with Desert Eagles in one hit 5 times.
- Breach and Clear
Kill a player with MP5 from 30m(?) or less 5 times.
- Russian Efficiency
Kill 3 players with the AK-74 without reloading.
- Ammo Conservation
Kill 2 players with Steyr-AUG without reloading.
- Deer Hunter
Kill 3 players with Ruger without reloading.
- Eagle-Eye
Kill a player with Barrett M82 from over [1 screen's distance] away.
- Concealed Carry
Kill 3 players with US SOCCOM without dying.
- Ninja training
Kill 3 players with a knife without dying and without firing a shot.
- Artistic mess
Kill 3 players with a chainsaw without dying.
- Respect the LAW
Kill 3 players with M72 LAW without dying.
