This machine is the Big Bad from the "Operation Rimfire" adventure for the Mekton roleplaying game.
The GigaKaiser is a unique machine created by the Axis terrorist organization. It's protected by a forcefield (which made it very hard for the heroes to defeat) generated from the red node on the crotch. Those protrusions at the ankles house electronic warfare systems.
I originally planned for the GigaKaiser to be red, but once I actually got around to coloring it I liked this scheme better.
Anyway, the lineart for this image is copyright and everything R. Talsorian Games, no infingement intended nor implied, etc.