Coward Montblanc and Mozaik Role were composed by DECO*27.
Panda Hero composed by Hachi.
Campanella composed by sasakure.UK (sasakure-P).
Rosetta composed by monaca:factory.
More songs by GUMI you might enjoy:
Our 16bit Wars
The Last Revolver (aka "Goodbye my Lover")
Sorry for Being a Closet Otaku
Goodbye to Alice
I Want to Meet You (Aitai)
Sunset Love Suicide
The Love Will Surely Soar
For My Soul
Just A Game
Poker Face (Not a Lady Gaga cover)
Real Intention (I've only found this on Nico Nico, and as far as I know there's no translation.)
Lying, Crying Pumpkin
Time-Warped After Chopping a Stag Beetle
Idiocy (this one is only available on the CD "Official Orange" but I think you can find it on YouTube)
Jinsei Reset Button
My Crush Was a Monster Boy
A Childish Girl and an Adult's World
Listening to: Vocaloid
Reading: Basic book
Playing: Pro Evolution Soccer
Drinking: Plain water TM