Inspired by Tech Romancer, perhaps?

[ed_nabisco]

Tech Romancer is an awesome Capcom fighting game, with the main robot character, G. Kaiser. I had it on the Dream Cast and was one of my favorite games. I’m wondering if the developer was inspired by Tech Romancer, which was a game that was “inspired” by many popular Anime robot characters.

[Slagathor]

I think it's inspired by robot animes from the 70's-80's like Mazinger, Voltron, Red Baron ... take your pick. The game is somewhat simple, but I love the soundtrack and the ambience all together. Go Vulkaiser !

[MysteryK]

A combination of Gigantor and MazingerZ. That is how I see it.

[kevinshow]

Yep at one point, you can say any similar game is inspired by all of those giant robot shows or games. I could see this game's robot being replaced by Danguard Ace and Grandizer shoot-em up though, since they have a plane form also, though I guess all of them could generally fly in robot form so maybe having the plane form is moot.

[dq_177]

Both Tech Romancer and this game are homages to the same sort of material, that is why one makes you think of the other.

[Talint]

Inspired by Grendizer, for sure.
http://www.youtube.com/watch?v=tW8JKCouIA4

[Dabeavis]

Both were homages to classic mecha anime, albeit Tech Romancer homaged mecha anime as a whole since you had various mechs based on real robot animes like Gundam & Macross/Robotech as well as super robot ones (Pulsion even partially resembles an EVA). Vulkaiser's more in vein of Mazinger, Grendizer & Getter Robo.

[stray_pengo]

If anyone liked the soundtrack, google for Chumei Watanabe and Shunsuke Kikuchi, the two giant composers who shaped the musical scape of super robot genre (and of Sentai and Dragonball's, among others.) Those are whom the game does great job of paying homage to.

I wish they would release Vulkaiser's soundtrack. It never fails to put a smile on my face.

[HellFalcon]

Mazinger Z is among the best shmups ever realesed at my opinion.

[Bewul]

This game reminded me of a japanese playstation game called 70's robot anime Geppy-x! hard to find decent gameplay vids, so linking a longplay of it, just watch teh start.
https://www.youtube.com/watch?v=PK40nei37CU

a shoot'em up poking fun/doing an homage to old combiner robot animes.