The option has two modes, defense and offense. In defense mode, it circles your ship and will absorb bullets and damage enemies it touches. In offense mode, it will seek out the enemies without requiring any intervention on your part -- however, it no longer acts like a bullet catcher in this mode. You can instantly switch between either mode by pressing the secondary fire key.
The option in offense mode will attack enemies, but it also overheats easily and will be slow to attack enemies until it cools down. This randomizes its behavior a bit so it just doesn't instantly kill everything. (Kind of like the little spinny option in Hellfire.)
Absorbing bullets gives you a little score bonus, while destroying an enemy with the Orb will net you extra points. Still tweaking these settings, though, so that might change in the future.
The game is freeware and will be available pretty soon. There's a demo on the website, but it's for the old version that doesn't have the new manic-like modes like the ones in the video.
Ghegs: Originally the bullets were much faster, but a friend suggested I slow them down and when I did it gave it a much more frantic feel. I've tried to keep the levels consistantly throwing stuff at you, especially on hard mode. I hate lulls in action too.
And no, I never did try W-Ring (never owned a PCE/TGFX16), but if it's similiar I would like to play it!