Z-Jumps are jump chains made up of glowing markers made by Zip that allow Blob to jump off surfaces, painting any attached buildings along the way.
The first Z-Jump was seen on the bridge in the Uptown section of Chroma City. They were at first introduced by the name Zip-Jump, but throughout the rest of the game they are referred to as "Z-Jumps". The main use of these is to navigate areas. They are mostly used for purposes of elevation.
To use a Z-jump, you basically stand on an available Z-jump marker, press Z, and shake the Wii remote. The result will have Blob to jump to the next Z-mark. When on a Z-mark, simpily press Z and shake the remote again to go to the next. Continue this process until you hit an X-mark, in which the Z-jump chain will end. If you wait too long before jumping on a Z-mark, you will eventually fall off the marker and have to start the chain over again.