|“||Move the Blobs left and right. Press a button to spin the Blobs. Press down to speed their fall. If four of the same color attach to each other, they will explode.”|
|— Tutorial • Kirby's Avalanche|
Blobs are squishy, jellylike creatures with two large eyes. They come in five colors: red, yellow, green, blue, and purple.
Pairs of colored Blobs drop from the top of the screen. The player must rotate and move the groups before they reach the bottom of the screen or land on the pile, so that matching-colored Blobs touch. When four or more same-colored Blobs connect, they explode, causing any Blobs above them to fall down and fill in the space. If the player manages to set off a chain reaction, an avalanche occurs; Blob-like Boulders fall on the opponent's screen. The number of Boulders that falls depends on both the number of Blobs destroyed and the number of consecutive chain reactions—up to 36 can be dropped at once. These Boulders can only be destroyed if a player manages to explode a group of Blobs that are in direct contact with the Boulders.
If the third column from the left piles up to the top of the screen, the player who allowed the pileup loses.
- The Blobs did not originally appear in the Kirby series. Kirby's Avalanche is a clone of the Super Famicom game Super Puyo Puyo; in this game, Blobs are known as Puyos. Blobs also appear in Dr. Robotnik's Mean Bean Machine, a Sonic the Hedgehog-themed clone of the Sega Genesis version of Puyo Puyo.
- Garbage Blobs are referred to as Boulders in the North American version and Ghosts in the European version, to fit the different regional titles of the game.