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.
Space 250 Goons
Mass Retreat 5 Times
Collect 10,000 Rez
Beat a Warpgate 10 levels higher than you
Destroy 500 Enemy Ships
Explore 10 Star Systems
Collect a Common Specialist
Complete 25 Missions
Collect an Uncommon Specialist
Train a Specialist to Expert
Bribe Past 5 Warpgates
Bribe Star Relations 5 Times
Destroy 100 Enemy Ships
Collect 250 Goons
Reach Tech Level 10
Collect 1,000 Rez
Collect a Godlike Specialist
Feed Santa so much milk and cookies, that an elf falls off his sleigh
Complete 5 Missions
Escape the Sol System
Repair the Clockwork
Destroy 2500 Enemy Ships
Collect 100,000 Rez
Collect 2,500 Goons
Collect 25,000 Goons
Destroy a Tier 3 UTA Base
Destroy a Tier 3 CIV Base
Destroy 25 Starbases
Explore 50 Star Systems
Explore 150 Star Systems
Complete 100 Missions
Collect a Rare Specialist
Collect an Elite Specialist
Reach Tech Level 50
Reach Tech Level 100
Research a Category to Level 10
Unlock All Ship Hulls
Unlock All Components
Upgrade the Clockwork
The Clockwork II
Complete the Game
Complete the Game on Expert
Complete the Game on Insane
Never use Respec
Clear all zombie infection
Retire a Specialist
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.