Field Surgeon - 10
Heal 3 team members for at least 50% of their health within 1 minute
This is easy to arrange with a team of 4 in coop, especially on harder difficulties. Your squad heal app makes this really easy. Just wait until everyone's damaged below 50%, and pop it.
Oh no you don't!
Complete 10 Contracts against members of your syndicate
For this, you will obviously need to be in a Syndicate. A contract is when a player is further along in a challenge than you. You can complete this contract by exceeding them in that challenge (like getting more liquid kills, healing more syndicate members, etc). On the stats and challenges screen, your contracts will be on the right side. You will want to join a Syndicate that has players with the same amount of progress as you do, otherwise, if you join one with members that have been playing for a while, your contracts will be for ridiculous values.
High Flyer - 15
Score a 2,000 points combo
Combos occur from bonuses when killing enemies. Each type of bonus (sergeant, head shot, etc) will add an extra multiplier to the combo. An easy way to get this is to take damage link and C2C pulse when in a group. Damage link will give you points everytime an ally damages something else, and C2C will heal any damaged allies in range, also giving you points. Difficulty levels effect point values for enemies, so this might be easier for some on hard mode or above. Another easy way to get this is to be the last man standing, and begin raising your team mate as you continue to kill enemies.
Employee of the month - 10
Complete a mission after earning a team savior score
"Team Savior" is awarded for reviving your team as the last man standing. Simply let your team fall, reboot them, and complete the level.
In the name of Science
Finish your first research
Research is completed by using blueprint or application tokens on upgrades for weapons and apps. After tokens are used, that upgrade must be selected for active research. A little cog will appear next to the tech you are researching. This tech will have a progress bar and number listed; this is the amount of experience needed to finish the research. As you play, that bar will fill up behind the scenes and alert you when it's completed while on a mission.
Application Manager - 20
Do 10,000 points of damage and heal or block 10,000 points of damage using applications
This should come naturally with time. Shield, group heal, C2C heal, and e-drain can all count to healing (and damage, in the case of e-drain). Backfire, virus, and tentatively damage link can count to damaging. You need to do both 10,000 points of damage and heal/block 10,000 points of damage for this to unlock.
Middle Management - 50
50% completion (level, research and challenges)
CEO - 100
100% completion (level, research and challenges)
This is the long haul achievement for coop. You will definitely hit rank 30 and probably have the majority of your upgrades (52 for apps, 86 for weapons) before you're even close to finishing all of these. Any enemy that must be breached to be killed (Liquids, etc) can be shared between two people so long as you breach the final armor layer together, so you can easily cut down those grind times. Here's the list of what you'll need to accomplish for the challenges:
Total Kills: 5000
Includes all kills (even liquids, etc)
Spectre Kills: 50
Found in Cayman Global maps (1-3)
Electron Mace Kills: 100
This only counts people you kill that are holding the weapon. Sergeants in Colorado, China or Scandinavia.
Riot Lance Kills: 100
This only counts people you kill that are holding the weapon. Police in China or Scandinavia.
Riot Shield Kills: 100
This only counts killing police that are holding one. They show up in China and Scandinavia.
EMC Kills: 50
They are the guys that jam your DART chip and breaching abilities with the pulsing animation. EuroCorp levels (7-9).
Aspari Kills: 1000
All Aspari kills count to this on any Aspari themed level (4-6).
EuroCorp Kills: 1000
All EuroCorp kills count to this one on any EuroCorp themed level (7-9).
Cayman Global Kills: 1000
All Cayman Global kills count to this one on any Cayman Global themed level (1-3).
Police Kills: 100
These guys only show up in China and Scandinavia. They wear black attire, so you can tell them apart from the gred/red Aspari guys.
Mercenary Kills: 20
They will randomly spawn on Expert mode on a few levels. Western Europe, Colorado and Scandinavia are all confirmed places where they will show up. In Western Europe, they will drop near the first giant door. In Colorado, they will drop on the landing pad above where you start toward the end of the level. In Scandinavia, they will drop after you leave the warehouse. There's no sure-fire way to get these guys to show up, but when they do, around 7 of them will show up. This will be the most difficult challenge to solo, so grab a friend or three.
Liquid Armor Kills: 50
They show up in Cayman Global levels, but will be replaced in higher difficulties. Hard is probably the best balance of them. You might have to farm these, due to how uncommon they tend to be compared to reactives.
Electric Armor Kills: 50
These are EuroCorp faction units, so they show up in levels 7-9. They are functionally like Liquids, but emit electricity when ready for a chip rip.
Reactive Armor Kills: 50
They are in most levels, and are usually replacements for liquids/electrics on higher difficulty levels. They are more plentiful in the long run than either Liquids or Electrics, and you will encounter them on every level with Scandinavia probably having the least.
Agent Kills: 20
These are the enemies that usually show up at the end of the themed arcs. The following levels have agents:
Kills by Fire: 100
- Atlantic Accelerator:
4 Agents at the end
1 Agent in tunnels (hard difficulty or above)
4 Agents at the end
2 Agents at the end
- New England:
4 Agents at the end
Thermite thrower, COIL, and CQC shotgun's alt-fire will accomplish this. Since CQC is a loadout gun, it's easier to do it with that since you can reload it at any ammo box, and it has a decent range.