Time saver??

[TRICKY1976]

http://www.xbox360achievements.org/images/achievements/1708/+8hheA==.jpgTIME SAVER 20http://www.xbox360achievements.org/images/site/gp-g.png
save 300 seconds worth of time

How do you get this achievement???

[Reaper ECG]

The first level you can get this is level 15. Its collectable shaped like a clock and each clock will reduce your time by 3 sec.