Talk to Minikin and buy a high damage weapon with a fast burst rate and large magazine, such as the Oblivion-Arc 1. Play the "Space Plumber" mission. Quickly run through the mission collecting all the money packs and killing the zombies. Sometimes the zombies will drop money. It takes approximately two minutes to complete the mission and collect all the money. You will get around $20k per run. Keep replying the mission and collecting the money as many times as desired.
Various Steam Achievements
Complete the indicated task to unlock the achievement.
Achievement
How to unlock
Awakening - Cat person
Kill every dog in the level without getting hit.
Awakening - Hood in space
Finish the mission with accuracy higher than 70 %.
Awakening - Somebody wants to be rich
Collect every credit in the level.
Awakening - Who let the dogs out... seriously
Finish the mission on any difficulty.
Base defense 1 - Can't touch this
Do not get hit for 1 minute.
Base defense 1 - Die right now
The door controls can't get under 50 %.
Base defense 1 - Don't touch my stuff
Finish the mission on any difficulty.
Base defense 1 - Paralyze this
Kill 3 enemies with the paralyzer.
Biohazard - First waves are easy
Finish the first Biohazard mission.
Biohazard - More waves incoming
Finish 20 Biohazard missions.
Biohazard - No wave can kill me
Finish 50 Biohazard missions.
Biohazard - That is a lot of waving
Finish 30 Biohazard missions.
Biohazard - What comes next?
Finish 10 Biohazard missions.
Biotech device - Crystallized
Finish the mission on any difficulty.
Biotech device - I can do better
Finish the mission in less than 10 minutes with accuracy higher than 70 %.
Biotech device - Ordinary person
Finish the mission without using any special ability.
Biotech device - Secondary fan
Finish the mission using only the secondary weapon.
Collector of Oddities
Get at least five unique weapons.
Drone chip - Credits everywhere
Find all credits in the mission.
Drone chip - Drone buster
Kill the drone in less than 60 seconds.
Drone chip - Drone guts
Finish the mission on any difficulty.
Drone chip - Untouchable
Finish the mission without taking any damage.
FB - Now just run
Fully upgrade 3 abilities.
Find way out - Bullet saver
Kill 5 enemies with one magazine.
Find way out - Lost in space
Finish the mission on any difficulty.
Find way out - Tablet lover
Collect every tablet in the level.
Find way out - The doctor is in
Successfully remove 10 zombie parts.
General - Am I a Zombie now?
Use revive (checkpoint) for the first time.
General - Are we there yet?
Travel 15,000 m.
General - Are you gonna cry?
Die 20 times.
General - Bullet waster
Fire 5,000 bullets.
General - Croucho man
Travel 600 m crouched.
General - Curious
Loot 10 lockers.
General - Devastator
Kill 600 enemies with the shotguns
General - Do you legs burn?
Travel 1,000 m crouched.
General - Exterminator
Kill 10 boss enemies.
General - Full pockets
Loot 100 parts of gear or implants.
General - Full throttle
Finish 50 generic missions.
General - Getting low
Travel 400 m crouched.
General - Getting to know the place
Travel 10,000 m.
General - Gravedigger
Kill 10,000 enemies.
General - Great cyberwolf
Finish 10 lone wolf missions.
General - Handjob
Kill 20 enemies with melee weapons.
General - Hard to kill
Use 10 revives (checkpoints).
General - Hunter
Kill 500 enemies.
General - Immortal
Use 50 revives (checkpoints).
General - Intrigued
Loot 50 lockers.
General - Itchy finger
Fire 500 bullets.
General - Johnny Walker
Travel 20,000 m.
General - Keep on dying
Die 10 times.
General - Killer
Kill 1,000 enemies.
General - Long road ahead
Finish 1st generic mission.
General - Looter
Loot 100 lockers.
General - Lord of the Loot
Loot 3,000 parts of gear or implants.
General - Lucky
Finish the mission with less than 5 % health.
General - Machine gunner
Kill 1,600 enemies with the machine guns.
General - Machine handler
Kill 800 enemies with the machine guns.
General - Machine rookie
Kill 200 enemies with the machine guns.
General - Mengele
Successfully remove all zombie parts.
General - More dead than alive
Die 100 times.
General - New perspective
Travel 200 m crouched.
General - Nothing more to be done.
Finish all generic missions.
General - Pandorum
Spend 20 hours on the ship.
General - Perfect aim
Kill 25 enemies with headshots.
General - Picking up speed
Finish 10 generic missions.
General - Pistol lover
Kill 500 enemies with the pistols.
General - Pistol tester
Kill 100 enemies with the pistols.
General - Pistoleer
Kill 1,000 enemies with the pistols.
General - Practice makes perfect
Replay the same mission 10 times.
General - Pusher
Kill 150 enemies with the shotguns.
General - Racist
Kill 10 enemies of the same type in a row.
General - Shot Gunner
Kill 1,200 enemies with the shotguns.
General - Slayer
Kill 5,000 enemies.
General - Slow and deadly
Travel 800 m crouched.
General - So the Journey begins
Travel 1,000 m.
General - Stretching my legs
Travel 5,000 m.
General - Sucker
Retry the level 10 times.
General - Tech collector
Loot 1,000 parts of gear or implants.
General - This happens to everyone
Die.
General - Too hard?
Die 50 times.
General - Trigger digger
Fire 50,000 bullets.
General - Up close
Kill 50 enemies with melee weapons.
General - Who needs guns?
Kill 100 enemies with melee weapons.
Get connected - Electrician
Finish the mission using only the paralyzer.
Get connected - Headman
Kill every enemy using headshots.
Get connected - Is there any Wi-Fi?
Finish the mission on any difficulty.
Get connected - Nope it won't work
Shoot the forcefield 10 times.
Get Minikin - Dodged that!
Do not get hit by the boss's ultrasound wave.
Get Minikin - Old-fashioned
Finish the mission without using abilities or the paralyzer.
Get Minikin - Wakey Wakey!
Finish the mission on any difficulty.
Get Minikin - Who needs GPS?
Find an elevator card without being told.
Hangar sabotage - Glass half full
Finish the mission with more than 50 % of health.
Hangar sabotage - Seppuku
Finish the mission on any difficulty.
Hangar sabotage - Suck it Grim Reaper
Use the medikit or medibag with 3 % health left.
Hangar sabotage - Who needs ammo?
Don't collect any ammo boxes in the level.
Hell at the End - Glass half empty
Finish the mission with less than 50 % health.
Hell at the End - Out of breath
Finish the mission in 3 minutes.
Hell at the End - That just sucks
Die just before the end.
Hell at the End - To be continued...?
Finish the mission on any difficulty.
Hub - All the help I can get
Buy 500 bonus items.
Hub - Balancing the scale
Buy your first bonus item.
Hub - Big spender
Spend 500,000 credits in the HUB.
Hub - Bigger Rohn Jambo
Buy 5 weapons.
Hub - Biggest Rohn Jambo
Buy 10 weapons.
Hub - Cyber me up
Collect all pieces of any legendary or epic implant set.
Hub - Cyborg
Buy 100 implants.
Hub - Dividing the love
Upgrade 5 abilities.
Hub - Double threat
Fully upgrade 2 weapons.
Hub - First paycheck
Spend 100,000 credits in the HUB.
Hub - Happy armory
Fully upgrade 3 weapons.
Hub - Human improved
Buy your first implant.
Hub - Human upgraded
Buy 10 implants.
Hub - Learning new tricks
Unlock 3 abilities.
Hub - Little Rohn Jambo
Buy your first weapon.
Hub - Magician
Unlock 10 abilities.
Hub - Make it better
Buy your first upgrade.
Hub - More help please
Buy 50 bonus items.
Hub - More upgrades please
Buy 10 upgrades.
Hub - Need a bigger closet
Buy 10 armor pieces.
Hub - Need a bigger house
Buy 100 armor pieces.
Hub - Next please
Upgrade 3 abilities.
Hub - Nice start
Upgrade your first ability.
Hub - Proper weapon
Fully upgrade the first weapon.
Hub - Shopaholic
Spend 1,000,000 credits in the HUB.
Hub - Suit up
Buy your first armor piece.
Hub - Upgrades all around
Buy 50 upgrades.
Hub - What does it do?
Unlock your first ability.
Hub - Who needs weapons now?
Fully upgrade the first ability.
Hub -Tailored suit
Collect all pieces of any legendary or epic armor set.
Life Experiment - (E)Met
Finish the mission on any difficulty.
Life Experiment - Better stock up
Collect every ammo box in the level.
Life Experiment - Fast and accurate
NFinish the mission in less than 8 minutes with accuracy higher than 80 %.
Life Experiment - Steady aiming
Kill 5 enemies while crouching.
Missing component - Primary fan
Finish the mission using only the primary weapon.
Missing components - I can haz no deathz
Finish the mission without dying.
Missing components - No door unturned
Open all the lockers in the level.
Missing components - Where did I put it?
Finish the mission on any difficulty.
Oxygen fix - Close to the edge
Your health dropped under 15 % three times.
Oxygen fix - Getting some air
Finish the mission on any difficulty.
Oxygen fix - Orb lover
Collect every orb in the level.
Oxygen fix - Precision aiming
Kill at least half of the enemies with headshots.
Reactor battery - Everybody on board
Kill more than 50 enemies in the mission.
Reactor battery - Full charge
Finish the mission on any difficulty.
Reactor battery - Machine Killer
Finish the mission with accuracy higher than 90 %.
Reactor battery - Mathematician
Disable the force field before you are told to.
Revive Razor - Clear
Deal the final blow to the boss with the paralyzer.
Revive Razor - Devil's number
Never use more than six attacks with one weapon.
Revive Razor - Frankenstein
Finish the mission on any difficulty.
Revive Razor - Gunman
Do not use the iron sight for the duration of the mission.
Server takeover - Hacking is fun
Finish the mission on any difficulty.
Server takeover - Home prison
Do not leave the center room.
Server takeover - Slow agony
Kill every enemy in the mission without a headshot.
Server takeover - Switching is for cowards
Finish the mission using only one type of weapon.
Supersoldier - Control yourself
Finish the mission without using any special abilities.
Supersoldier - Eye of the bull
Kill at least 5 enemies with headshots without reloading.
Supersoldier - They can what now?
Finish the mission on any difficulty.
Supersoldier - What explosives?
Do not use explosives for the duration of the mission.
Survive - Final countdowner
Finish 10 Survive missions within the specified time limit.
Survive - Housekeeping
Finish 20 Survive missions within the specified time limit.
Survive - Spilling some blood
Finish the first Survive mission within the specified time limit.
Survive - Survivalist
Finish 50 Survive missions within the specified time limit.
Survive - Unstoppable
Finish 30 Survive missions within the specified time limit.