Long before Flappy Bird and similar mobile plagues, one title on the PC was the main enemy of computer science teachers. It was Icy Tower, a 2D platformer that came out in its 1.0 version to this day, 20 years ago. Simple premises, but challenging mechanics, Icy Tower quickly became popular primarily because it was a freeware game or free title. He also benefited from the fact that it could be downloaded with the then 56K modems because it weighed only a few megabytes.
Icy Tower was inspired by a similar Xjump game for Linux. The point of the gameplay was jumping upstairs, with the main character Harold the Homeboy being able to bounce off the walls. In the beginning, the platforms on which to jump were wide, but after every hundredth floor they became narrower, and the camera moved faster and faster upwards, so the player had less room for mistakes.
Later versions of Icy Tower got a competitive scene with online charts and the ability to share replays. After version 1.2 players could choose the look of the floors and the main character, and after version 1.3 the game became even more challenging as the platforms shrunk after the thousandth floor.
Icy Tower has received numerous ports and various editions for Facebook, iOS, and Android. Even today it can be played for free. Unofficially, the game also appeared on the Nintendo DS and PlayStation Portable consoles.