After taking pains to tell us that the game's major fault is its short length, that it can "be beaten in a single evening" (possible, if you do nothing else for several hours) it tells us that the game has a bit of replay value since, by finding all the hidden switches, the player can get a better ending.
This is not true. More recent Kirby games have instituted this as the incentive for finding all the secrets, but the ones directed by Kirby creator Masahiro Sakurai (the Smash Bros. guy), which includes Kirby's Adventure, use new game modes as their super-lockables. In Kirby's Adventure, this is the challenging "Extra Game," which is the answer to Gamespot's other problem with Kirby's Adventure, that it is too easy.
But let's stick with the true problem, why Gamespot's review is wrong:
There is no better ending. They did not play the game through.Maybe someone relied on a faint memory of the game from the NES era, but considering that they say the game is short, there is really no excuse for them not having played through it again. The reviewer should have known there was no better ending to be had.
It also casts doubt on the validity of their score of 7.3, for what is one of the best games on the NES.
Funny thing is, the guy who reviewed that is an independent journalist who gets commissioned to review games. Notice he doesn't have a game page like other GameSpot editors do.
This is the same guy that gave Yoshi's Island DS a 9.1, and everybody else gave it 6s and 7s.