Okay, I played through both the Sariel and Konngara scripts, so here's some comments from a novice Danmakufu scripter. The comments may seem a bit pretentious with me ordering you around or something, but I'm not really trying to be like that D: This is technically my first time giving some sort of input, so I hope I help somehow.
1. Default Danmakufu bullets. Please don't use them. They just look really ugly (at least to me), so it ruins the aesthetic part of the danmaku (since beauty in danmaku is basically the whole point, heh). In Konngara's fight you definitely used the Expanded Shot Data for part of the script, so why not use it for the entire battle? The butterflies and icicles (RED22 and RED23, respectively) especially stand out as one of the worst bullets in the entire fight.
2. Forced no-vertical. This has already been addressed by Naut, but I'll just add my own comments about it. It works out fine in a game like Highly Responsive to Prayers, but in an actual danmaku game I don't think it's very convenient, especially when you're trapped in the corner and you can't whack the bullets with a gohei or get rid of them by throwing cards. Plus, when a spell card activates, I kept forgetting that I had free movement, and kept trying to no-vert all the cards despite me not having to. (I hope I'm not the only one doing that.) Since it's a danmaku game, maybe it'll be better to extend the movement area a little? (Such as restricting the movement area to a third of the screen, though I don't even know if that's possible...)
3. Difficulties. You've already addressed the fact that it's hard to differentiate from Easy and Normal difficulties, but I'll just add my own comments about it (again). The few differences I see between Easy and Normal is a. the speed of bullets, and b. the frequency of bullets being shot (such as those purple bullets in Cocytus). There aren't really many times where the number of bullets change at any given time, which I think is the reason why Easy is so similar to Normal. Of course this is just from what I see, because it's difficult for me to look into the scripts and understand what's exactly going on...
4. Repetition. Konngara's nonspells were terribly boring, because they were all exactly the same. Really not much else to say about it... ._.;
I think those are the only bad things that really stood out to me as I played it. Otherwise, everything else is pretty cool. The ghost tail effect (on Konngara as well as the homing purple bullets) was amazing, although the bullets are hard to dodge ;_; Phlegethon looks amazing, but is really really difficult. Some of the other effects (like the curving lasers in the nonspell) are also cool, but the curving lasers are difficult to read. I guess my final conclusion is that the patterns are cool, but too difficult for me to play.
Oh, and a personal dislike I have is the Touhoumon sprites, which look unprofessional for scripts like these. But I didn't want to officially complain about it in the list above because it's not something that's easily changed in future scripts, plus I can't make sprites either so yeah ._.;
But the scripts are really amazing in terms of being hard to actually create in Danmakufu, since the patterns look pretty complicated to make. Like Naut said, working on the aesthetics will really make the scripts great. Hope to see more in the future!