Omega Supreme is battery operated.  His tank mode works perfectly!!!  His head will light up with a red light (see pic).  The head will turn 360 degrees around as the tank rolls.  The red tank turret will also bob up and down as the head rotates.  The tank mode works 100% with zero issues when batteries are installed.   

NOTE:  Omega Supreme no longer walks in robot mode.  A white node cracked off in his left leg (see pic with my thumb pointing to the cracked interior node.  Nothing is visible from the outside, but he no longer walks in robot mode.  That's the only draw back.

NOTE:  Omega's backpack has a cracked right front corner.  There is not enough material to super glue it back in place.  It was a flimsy design.  Note the issue and look at all of the pictures.