Dropped a few more credits on this last night, and have got a few more thoughts.
I've been playing a fair amount of Battle Garegga, Esprade, and Mahou Daisaukusen on PS4 over the last month or so (Garegga for a few years here and there). The amount of care and heart put into the Shot Triggers releases is unreal. For a shooting game fan, the Shot Triggers releases are like an actual dream. The amount of customization possible is kinda overwhelming at times, but ultimately makes for the most fulfilling experience.
By contrast, this Mushihimesama release feels really bare bones, I'm sorry to say. You can rotate the screen, but I don't see a way to actually change the size of the screen. In other words, you can rotate the screen to play vertically, but the actual play screen is still the same size as it is by default. In that case, what's the point of even including that functionality? I'm still enjoying it a quite a bit, and this is far and away the most I've ever played the game, but every other STG released on modern consoles seems to have a full size vertical option (even games on PS1 and Saturn offer this), and I don't get why they didn't include that here.
Ultimately, the best way to play this particular release is on a big ass TV and a stick. I can't imagine playing this seriously in handheld mode really at all, but I guess that kinda goes without saying.