I've played all three of my purchases very lightly, but here are my impressions:
Hisyou-Gumi is the best of the three I got. Hori shmup where you gain experience by collecting blue orbs that enemies drop. When at max level the orbs give points instead. You'll hit max by early stage 2; in Easy you don't lose levels unless you game over, but Normal and Hard bump you down every time you die. If you stop shooting, orbs will rotate around your character blocking bullets and destroying certain obstacles that are aren't damaged by your shot. It defaults to Easy Mode with 9 lives and even if you bump the difficulty up I suppose 9 lives is still the default. It's competent but a bit bland - one of those cute em ups that doesn't really have charm or personality though it ticks the boxes. I think Hard mode might be good.
B-System is wants to be Darius+Gradius, with mecha fish bosses and a Gradius-style upgrade system. Unfortunately, it seems to just be an uninspired boss rush. If you like boss milking this may be for you - it seems that destructible boss shots are the only things that give points, the bosses themselves don't seem to. Seems like the worst of the lot.
Titei Senki isn't a scrolling shmup at all - it's one of those games where you destroy all the enemies to open a goal. You control a sidescrolling mech game with infinite boosting and weak gravity - basically a flying game as long as you keep tapping up. You can switch between two (straightforward) weapons at will, and the recoil from shooting will push you back. I only played the first stage (consisting of six areas) and didn't care to continue, but that might have been the expectation gap and the fact that I usually don't go for this kind of game. Hard mode has some promise; Normal didn't do anything for me and seemed a little light (though, again, I just saw it through stage 1).
All three seem to be X68000 ports, judging by the group's work on that system and the fact that all the title screens indicate copyright dates of 1997/2016. It looks like I have Xadlak Plus in my library at DL Site though I don't think I ever played it - it's probably OK though.
Since we're talking DL Site, anyone know about
Rayhawk? I'm extremely skeptical looking at their list of very similar games.