I have been trying it, thanks to the magic of bittorrent.
I have been messing around a lot, especially Sanae Kochiya A. For a very stupid reason:
Her spellcard
Yes, a motherfucking huge snake. Of course, her other mode is as fun, her spellcard B is like FROG NUKE! In other word, she let something that looks like a vortex go. Then after roughly two seconds, the thing go off like a nuclear explosion.

The game is not really forgiving, you tend to lose a lot when you lose your life, the scoring system with the ufo is rather fun to do in the middle of a heated grazing session.
More about the UFO system thanks to Phean:
Gaining life/bomb
It’s quite new and it can be a blessing or a hell. First you need to gather the coloured UFO’s and if you have a three of a kind ( 3 red/blue/green ) you’ll get a big UFO on your screen to get shot down. Depends on the colour it drops different things.
Red: this one drops a 2/5 life and release everything that he had gathered. If you let him gather up to 100% he’ll drop another 2/5 life
Blue: Everything he gathered he’ll drop and you’ll get point bonus depends how many he had gathered.
Green: Same as the red one, but with bombs
You also can have three different colour in that case the power item he gather with have double value.
At this point, depending on the character, and the challenges you set yourself, it is more profitable to go for bigger score, more life or more bomb. As example, Sanae’s shots tends to be on the weaker side, but it is offset by her bombs, especially Frog Nuke; therefore, going for bombs and lives first over scoring may not be a bad idea.
The UFO system pushes the player to be a little more audacious and daring. Especially when you are in need of those life, bomb or score bonus and seek a special combination. More than often, you’ll find yourself in trouble for grazing in a bad spot while you were pursuing the ufo that switched to the color you wanted.
On the bosses. One of them, the headtowel wearing trap/reverse trap makes me wonder what the hell ZUN has been drinking again. So now Gensokyo is welcoming folks from 1001 Nights? Oh well, after lunar aliens and vampires, nothing should surprise me anymore.
Oh yes, TITANOBOA and Frog Bomb. I liked Sanae a lot already, thanks to Happy Flame Time‘s doujins, but now I am liking her even more. And Sakuya’s absence does not appear to me as much of a big deal. Maid already have like four games for her.