try it out, you'll see just how similar it is.
also found a number of gradius references...
the "mad moai" enemy, complete with demon horns
moai head platforms from the same stage
this one is kind of a double reference -
- a secret from stage 4 in gradius, very subtle
the entire area feels like planet ratis from salamander/life force, solar flares and all
it just so happens that iga got his start with konami working on gradius 2.
it's nice to see he hasn't forgotten his roots.