Here is the full list of all 30 ICEBOX: Speedgunner achievements.
Access the secret “Making Of” area
Access 10 hidden panels
Access 50 hidden panels
Destroy 10 loot signs
Destroy 30 loot signs
Acquire 1000000 total points
Die 100 times
Collects 100 Checkpoints
Kill 1000 Sentients
Kill 50 enemies with a headshot
Kill 300 enemies with headshots
Collects 150 Health pickups
Collect 500 weapons
Use Glitch 250 times
Start your first level
Explode 300 Red Crates
Access 200 Terminals
Destroy 150 Mines
Destroy 50 Mine/Fire Launchers
Collect 500 Technitium Pickups
Complete the Tutorial
Complete 10 Mixed Bag Games
Complete 20 levels from Escape The Icebox
Defeat the Central AI
Complete a Short Marathon
Complete 3 levels within 3 sec of par time
Complete 3 levels with less than 10% health
Complete 10 levels with more than 90% health
Complete 25 levels on Expert
Complete a Long Marathon