Yoshi

Yoshi, known as Yoshi's Egg (ヨッシーのたまご) in Japan and Mario & Yoshi in Europe and Australia, is a puzzle game for the NES and Game Boy. Both versions were first released simultaneously in Japan on December 14, 1991, and released in all other regions the following year. The NES version was later released on the Wii Virtual Console, the 3DS Virtual Console, and the Wii U Virtual Console.

In Yoshi, the player is tasked with clearing monsters from the on-screen playing field. The monsters fall in from the top of the screen to build vertical stacks; the player must prevent a stack from growing too high such that it exits the play field. In order to so, the player swaps and moves the stacks about such that falling monsters collide with identical monsters stationed atop the stacks, causing them to be removed from play. Yoshi offers both a scoring-focused single-player mode and a competitive two-player mode.

Gameplay
Yoshi is a falling block game in which the player is given a playing field that is divided into four columns. The objective is to match Yoshi egg shells to hatch them and prevent the four stacks, which pile up from the falling monsters, from growing too tall. The player character Mario swaps the stacks around such that the falling monsters will be eliminated by coming into contact with the blocks they match.

Monsters, which consist of various Mario enemies, appear at the top of the screen and fall into each of the columns, turning into blocks as they land and creating stacks that incrementally grow in height. The main objective is to prevent the four stacks from growing too high by eliminating blocks from the field; a game over occurs when any of the stacks crosses the black line drawn across the top of the play field.

To eliminate a block from the top of a stack, it must come in contact with a falling monster that matches it. For example, if a Goomba falls directly onto a Goomba block, both will be removed. The player controls Mario, who resides below the playing field and has the ability to swap the positions of any two adjacent stacks at a time. Thus, the player is required to switch around the stacks to ensure that the monsters fall into the correct places. Points are awarded for each set of monsters that are eliminated.

In addition to the four different types of monsters, two halves of a Yoshi eggshell will also fall. The bottom eggshell half behaves like a monster: it disappears when it comes into contact with another bottom half. However, if a falling top half comes into contact with a bottom half, the two will join and hatch a Yoshi, earning the player bonus points. Furthermore, if a stack of monsters grows atop a bottom half and a top half is then added, all monsters between the halves will be encased and eliminated. Larger Yoshi characters will hatch depending on the number of monsters encased, which also increases the number of bonus points awarded. If a falling top half does not have any bottom half to join to in the stack it touches, it is automatically removed and no points are awarded.

Game modes

 * A-Type: The game is played indefinitely until the player receives a game over.
 * B-Type: The player plays a series of levels in which the player is required to completely clear the playing field of all the blocks. The initial number of blocks inside the playing field grows as the player progresses.
 * Multiplayer: A second player controls Luigi. The two players play simultaneously in separate playing fields using the traditional rules. A player wins the match by clearing all the blocks in the field or when the other receives a game over; the first player to win three matches wins overall.

Mario and Luigi
Mario is in control of the trays, and can move side to side depending on which trays he'd like to swap (indicated by hand position). His goal is to hatch Yoshi eggs by connecting the top half of an egg with the bottom, and he must eliminate monsters along the way by matching them with monsters of the same type. In multiplayer mode, the second player takes control of Luigi.

Monsters
Goombas, Bloopers, Boos, and Piranha Plants are the enemies that must be eliminated. They drop down commonly from the top of the screen in the form of blocks. To eliminate them, match them with a block of the same type or hatch an egg that surrounds them.

Yoshi
The game's title character is also the goal; hatch as many eggs as you can in order to create Yoshis and obtain a high score. A counter to the right of the screen keeps track of how many eggs you've hatched and by extension, how many Yoshis you've collected.