Here is the full list of all 12 MicroBot achievements worth 200 gamerscore. It takes around 10-12 hours to unlock all of the achievements on Xbox 360.
Kill 25 enemies while using the Co-op Link Gun
Collect 'em all - parts, that is
Collect all 20 Bucky Balls
Beat 3 rounds in Challenge Mode
Equip a bot with only max level parts
Amass 50,000 Atoms
Beat a level using only movement parts
Find the source of the hostiles and destroy it
Kill 1000 Bacteria
Complete the 1st of 5 worlds
Kill 25 nanite enemies that emerge when you kill host organisms
Enter the body