Way way back in 'the day', defined loosely as the era between when I was 15 and 17, my obsession in gaming was over Kirby Super Star for the SNES. My cousin in tow, I would play KSS time and time again, avidly trying my damndest with Nintendo Power as my guide to find every one of the treasures in Great Cave Adventure.
Kirby Super Star Ultra is every bit as much Kirby Super Star as you remember, except even better. The silly minigames of Megaton Punch and the samurai showdown thing that is not, in fact, Samurai Showdown, have been taken out in favor of implimenting Mario Bros 64 DS-esque touch-screen sensitive ones. The game has been restored to its former glory, upgraded graphics and sound for the DS, and with the Metaknight himself as an unlockable character! It is a complete blast.
Go backwards about...a year? Yeah, I think a year. I pick up Kirby Squeak Squad, thinking, oh shit son, maybe it'll be like Kirby Super Star? I was sadly disappointed. KSS's main point of unbelievable fun was the multitude of different attacks each Hat had. Ninjas could explode after taking damage, throw shirukens, wall cling, and running slash. Most of these - wall clinging, for example - were hilariously pointless. But it was still loads of fun, finding each successive hat and discovering the new tricks you could learn. Squeak Squad didn't have this, and was merely one game of Kirby on the cartridge.
But Kirby SSU is the excellent Kirby Super Star brought to DS with new features. What more do you want? The reason I bought it was simple; Kirby Super Star isn't working on the version of SNES9x for PSP I have.