Here is the full list of all 48 Space Pirates and Zombies achievements. It takes around 100-120 hours to unlock all of the achievements on Windows.
Collect a Rare Specialist
Complete 100 Missions
Destroy 2500 Enemy Ships
Bribe Past 5 Warpgates
Explore 50 Star Systems
Collect 100,000 Rez
Destroy a Tier 3 UTA Base
Collect a Godlike Specialist
Reach Tech Level 50
Destroy a Tier 3 CIV Base
Collect 2,500 Goons
Bribe Star Relations 5 Times
Train a Specialist to Expert
Upgrade the Clockwork
Space 250 Goons
Destroy 500 Enemy Ships
Collect 10,000 Rez
Retire a Specialist
Explore 10 Star Systems
Complete 25 Missions
Collect an Elite Specialist
Collect a Common Specialist
Mass Retreat 5 Times
Reach Tech Level 10
Destroy 100 Enemy Ships
Collect 250 Goons
Collect an Uncommon Specialist
Escape the Sol System
Collect 1,000 Rez
Complete 5 Missions
Repair the Clockwork
Collect 25,000 Goons
Destroy 25 Starbases
Explore 150 Star Systems
Reach Tech Level 100
Research a Category to Level 10
Unlock All Ship Hulls
Unlock All Components
The Clockwork II
Complete the Game
Complete the Game on Expert
Complete the Game on Insane
Never use Respec
Beat a Warpgate 10 levels higher than you
Clear all zombie infection
Feed Santa so much milk and cookies, that an elf falls off his sleigh
Beat all 10 arena ladders and all 5 tiers on bronze, silver and gold level. Be the champ of 150 events..
Defeat a Tier 3 Bounty Hunter Stronghold in Chapter 4. In short, do the impossible. You have our sympathy.