What is this giant robot anime? Bugging me for years. I saw an anime in the early 80's (I assume it was from around then, since I watched it on a VHS tape) that featured a war between a group of pilots, maybe 3 or 4, that could join into 1 giant robot. This robot had a red head with red spikes kind of like the Statue of Liberty. The bad guys had giant robots that could join together too to form 1 giant super robot, and there were maybe 6 of them. 

I think it was feature length but possibly several episodes of a series put together. Also it seemed to me to not be childish. It wasn't adult but PG-ish. I recall it being sort of dark and sinister and violent. Please help me. Oh, and it wasn't Voltron or anything obvious like that.
You're probably looking for Getter Robo G. There's several TV series and movies based on this iteration of Getter. The movies are all cross-overs with other Go Nagai mecha franchises.


Getter Robo G
Great Mazinger tai Getter Robo G - Kuuchuu Dai-Gekitotsu
Grendizer - Getter Robo G - Great Mazinger Kessen! Daikaijuu


All from the 70's.