Everhood is by Chris Nordgren and Jordi Roca.

Powers Of Destruction (feat. Cazok)

Euthanasia Rollercoaster (Loop) (feat. KM EXP)

The In Stars And Time OST by Studio Thumpy Puppy.

plays vs the root of all evil. Credit to the creators/producers.

plays during the second tutorial raven gives. Credit to the creators/producers.

Original soundtrack from the indie game World of Goo.
http://kylegabler.com/WorldOfGooSoundtrack/ for more info.