I love the concept of the game a lot. Photo-shooters force you to think a different way and I really appreciate that. The music is also very nice, and appropriately fitting in my estimate. It is perhaps my favorite part of the game. The gameplay was a little confusing to start, certainly. Z being shield and X being shoot felt counter-intuitive and I often got caught up.
Once I got a hold of it, the challenge was brutal. The combination of slow cooldowns and the OHKO was especially killer, as shield and shoot both use up the same resource which means you have to choose between guarding and shooting, which extends the possibility of dying, which is a brutal punishment because one hit starts you right over again. Related to the cooldown is the fact it means you essentially have to either play aggressive-- and risk getting one-shotted-- or be conservative and choose between laser and bullet to clear (in the first stage for example.) And considering you can only do max 2 lasers per and about 4-8 bullets per, it takes a lot of cycles considering clearances were 15 and 50 respectively.
That said, there's a lot of good in this game too. Though I do admit being challenged and frustrated at points, it was still good fun. Oddly, I did encounter an issue where a dialogue between characters simply did not play on start until about my 10th time through... though I think that may be related to why I had difficulties starting up the game to begin with. Lol. But once I saw the portraits, they were very nice, with witty dialogue attached to them.
I'm not familiar at all with Seihou, but it seems you did them a pretty good service here. Nice job overall!