I'm rusty

[Sketchasaurus]

The design of the "professor" is very plain and doesn't feel like it would exist in the same universe as the robot. I'd definitely come up with a stronger design that communicates that the prof. is infact evil. part of effective design is showing the audience what a character's role is, this is where visual shorthand and archetypes come into play.

In addition, I'd probably make the prof. an older man since the robots are all rusted. either that, or he's a deranged hobo who builds robots out of rusted old scrap metal. anything goes, really.