The Four Food Groups: Goombas, Boos, Bloopers & Piranha-plants.
The puzzle game has to achieve an addictive quality, or, there really is no point in playing. Stacking endless tiles, bricks, blocks, or gems is not appealing in itself, so it must give the player satisfaction in this repetition. Everyone knows that "Tetris" achieves this, the newer crowd say that "Puzzle Quest" achieves this (I disagree), and I suppose the question here is; does "Yoshi" achieve this?
I prefer to side-step that question and just draw attention to the game's individual qualities. As mentioned earlier, the game-screen itself is very plain and static (apart from the ominously descending (and infinite) rows of icons), not much else moves. But, that's no problem. I can't think of a puzzle game that really is busy with animation that I care to play anyway.
Matching up two or more Goombas, Bloopers, Boos or Piranha-plants causes them to (shock) disappear, thus making room for more of the same. As a variable to this, matching up the top and bottom half of an egg (presumably Yoshi's) will give players either a bonus, or if you've filed the spaces between the two halves with other junk, it will all clear in one hit. It's a clever risk-reward mechanism that certainly beefs up the strategy element here.
As in other popular puzzle games, the options presented are fairly standard. Mysteriously titled (yet strangely familiar) choices between "Game A" and "Game B" are presented, as are choices for music and difficulty. We've seen it all before, but just not with these two mascots, right?
I know that I've put quite a few hours into this game (more than I have with say "Super Mario Bros."), so I believe that there is an addictive quality here. Sure, the music will drive you mad, and the trance-like state that it puts you in can't be too good for your alpha-waves, but there is a unique cuteness or innocence to this game that really gives it some appeal. Maybe it's the reunion of Mario and Yoshi in itself that gives this game a bigger audience than it deserves, but I still feel that it is a fair game in it's own right. Besides, anything with those little Mushroom Kingdom guys is always going to have charm.