Kirby Mass Attack
Yes, while your Kirby army is still building up, the game is pretty basic and boring -- unfortunately, even a full complement of 10 Kirbys plays pretty shallow. There simply aren't that many mechanics to exploit: just leading the army around by touch, or flicking individual Kirbys around, which is pretty difficult to do with any precision since they're all clustered together. Boss battles have the most complexity, where you'll have to lead the group away from obstacles, then rapidly sling them at a weak point when it opens. That's it.
I know it's wrong to expect significant depth or challenge from a Kirby game, but this is just unfulfilling. Not to say Mass Attack is bad, per se, but its uniqueness feels diluted and unremarkable, only really interesting for a few minutes. At least Epic Yarn's occasional tedium could be allayed by playing it co-op.
Progress: Gave Up -- Finished the first set of stages