Here is the full list of all 23 Kickback Slug: Cosmic Courier achievements.
Complete all main levels in Time Attack mode
Complete all levels in the Jungle Zone
Complete all levels in the Ice Zone
Complete all levels in the Mines Zone
Complete all levels in the Lava Zone
Complete all levels in the Space Zone
Escaped the planet after retrieving all lost parcels
Shoot the Blaster 5000 times
Use the Jet Crack 5000 times
Shoot your Cannon 5000 times
Collect 10 Packages
Collect 25 Packages
Collect 50 Packages
View all collected packages in the Gallery
Complete Level 2-7 using only the Blaster
Complete Level 3-3 using only the Jet Crack and with less than 8 Blaster shots
Complete Level 4-2 using only the Cannon and with less than 5 Blaster shots
Defeat the Mecha Fly Trap without failing once
Defeat the Mecha Yeti without failing once
Defeat the Mecha Mole without failing once
Defeat the Mecha Snake without failing once
Defeat the Mecha Dragonwasp without failing once
Defeat the Mecha Dragonwasp with more than 50% ship health remaining