In a lot of ways, this feels like the prototype to Donpachi, which makes sense, since Ikeda was the main programmer on this one (probably you all know this, if not, Ikeda was the main programmer on Batsugun
). The ship types basically map over to Donpachi ship types 1:1. The explosions sound pretty similar too. Seems like some ideas that would go on to kinda form the STG landscape were taking shape here.
On ship type - I think Type C is the most effective. If you hold button 1 down, you fire the laser type shot, which is very strong, but if you press button 1 rapidly, you fire a pretty brutal spread shot. This saved my ass a lot in later levels.
These are just my noob ass thoughts, so don't take 'em as gospel, but the popcorn enemies are likely what's going to take you out in the later levels, and they're often in the periphery. Type B wide shot sucks (and I think isn't even existent until you level up a bit), which increases the risk of getting popcorn'd even more.
Also, if I had to take a guess, I would say that Iceman is inspired by Yoshiki from X Japan:
Also, scoreboard updated!