When playing, Icy Tower players usually try to achieve good results in one of several existing styles of playing, known as categories. Players' achievements in any of the categories may later be published in any of the online communities established for that purpose. One of the methods that allow players to compare their results are online high score lists. Another are online tournaments in which they compete directly.

Icy Tower was created in 2001 by a Swedish game developer Free Lunch Design. New features are being added to the game both by its developers, who regularly release its newer versions, and by its players, who refine its gameplay by making custom skins and characters that refurbish the game and create separate applications and modifications that allow changing its default behaviour. Mobile and online versions of the program have also been made.

The game screen is fully occupied by a vertical cross section of a cylindrical tower, only a fraction of total height of which is visible at a time. The player starts the game on the ground floor of the tower. The character controlled by the player may move inside the tower and jump from one floor to another, but its movement is limited by the two walls of the tower and the semipermeable structure of the floors, which it can only penetrate from below. If the character ventures beyond the upper edge of the screen, the screen will follow its current position, so that it always remains within its scope.

After the character reaches the 5th floor the game screen begins to gradually move down. Since that moment the player's objective is to maintain the required pace of the character's ascent in the tower and not to fall below the bottom edge of the screen, which ends the game. The rate of the downward movement of the screen increases sharply every 30 seconds, which is equivalent to a rotation of the clock in the upper left corner of the screen. The clock breaks down after its fifth revolution, however, and the rate of the falling increases no further.

The goal of the player is to reach the highest possible floor and accumulate the highest possible number of points (score). Points are awarded for every single reached floor and for making special sequences of jumps. The physics of the game can be expressed in two principal rules:

It is also possible for the player to increase the speed of the character by hitting a wall of the tower (wall bouncing). To wall bounce a character it is required to direct it towards a wall and reverse the direction of the movement immediately after the collision. This technique makes it possible for the player to continue playing even if there is no space (or time) to accelerate the character on the floors themselves. The tower is of infinite height and it is impossible to reach the top. After the game ends, a recording of the character's progress in the tower can be saved in a separate file (replay) and viewed at will.

The length of the floors depends on their individual number, the version of the game, and a random factor. Their arrangement is entirely random. Their appearance changes visibly every 100 floors.[nb 3] Since the version 1.2 Icy Tower allows the player to choose the visual type of the floors on which each of his games. In order to do that, however, he is required to unlock the desired floor type beforehand, which is done by reaching a floor that bears that floor type by default. For example, if the player wishes to start the game from the fourth floor type, that by default belongs to the floors 300–399, he must reach at least the 300th floor first.

It is possible for the player to perform a sequence of jumps in the game, each jump spanning either zero, two or more floors. As long as the player reaches each floor within three seconds since reaching the previous one, such a sequence is called a combination (combo). A combo is the primary method of earning points in Icy Tower. For a combo to be rewarded with points, however, it must span at least four floors in at least two jumps, and subsequently one of the following conditions must be met:

Every completed combo is awarded a number of extra points, which is equal to the number of floors in the combo squared. A special notice (reward) displays on the screen after a combo is finished, contents of which depend on its length and the version of the game. Regardless of combos, the player is awarded a ten points bonus for every floor he has reached (which is revoked, however, if the player later descends from the given floor).

Icy Tower records players' best results in built-in high score tables. Every table contains data about zero to five Icy Tower games; a single table row represents a single game. Every game contained in a table is being defined by its results in a certain number of Icy Tower categories. Finally, all games in a table are sorted according to their results in a certain category, which is relevant and specific to the given table. Whether a given Icy Tower category partially defines a given game or not, as well as whether a given category has a separate table it is relevant to, depends on the type of the category and the version of the program.