I was just gonna talk about that stacking trick, though I was going to talk about the kind of trick used in EBA's Highway Star (Sweatin' / Hard ROCK!!) and Ouendan 2's MUSIC HOUR (Insane, maybe Hard), both times in the chorus. What I mean is when they stack notes, but time them in such a fashion that you can't SEE when you hit--you just have to know. (It's FAR more annoying in Highway Star due to the weird rhythm, whereas MUSIC HOUR is just on the beat.) The reason for this is that there's a big point burst covering up the circle beneath it.
Would that be its own thing, or would that be unrankable as well, despite it being used in the very games osu! is based off of? If it IS able to be called its own thing, I'd like to nominate it. I sadly have no pictures to display what I mean.
(BTW: Just got Ouendan 1, totally noticing how much I would hate the Hard maps if they were on the big screen (aka computer screen). Interesting, no?)