Complete the indicated task to unlock the achievement.

Achievement	How to unlock
Active Co-operation	Complete level 15.
Against The Gradient	Complete level 6.
All together now	Complete level 18.
Alternative energy	Complete level 11.
An exclusive bunch	Complete level 4.
Anti-co-operation	Complete level 19.
Anti-what?	Complete level 10.
Co-operation	Complete level 9.
Gradient Control	Complete level 8.
Hard Times	Complete level 21.
Heavy Lifter	Complete level 20.
Keeping it Real	Complete level 13.
Last but not least	Complete level 22.
Nano Robotics	Complete level 7.
Opposites	Complete level 14.
Punch through	Complete level 1.
That's a lot of particles!	Complete level 5.
Transporter, I said "Stop!"	Complete level 3.
Traveling in Groups	Complete level 12.
Two for One	Complete level 16.
Yo, they go from high to low	Complete level 2.
You have the power	Complete level 17.