Here is the full list of all 31 Chroma Blast achievements.
Killed Light with basic blaster
Killed Light with machine gun
Killed Light with rifle
Killed Light with burst
Killed Light with charge
Killed Light with telekinesis
Killed Light with gatling gun
Killed Light with shotgun
Killed Light with multi gun
Killed Light with charge cannon
Killed Light with energy gun
Killed Light with heavy machine gun
Killed Light with gauss rifle
Killed Light with rocket launcher
Killed Light with charge laser
Killed Light with knives
Killed Light with flak cannon
Killed Light with heavy burst
Killed Light with chain burst
Killed Light with charge burst
Killed Light with mind wave
Killed Light with gatling charge
Killed Light with blink
Killed Light with dancing blades
Killed Light with hyper charge
Killed Light with clone drive
Killed Light with psy gun
Killed Light with warp energy
Killed Light with heavy telekinesis
Killed Light with living energy
Killed Light with hyper telekinesis