John Mikula
Video Game Programmer

Jump n' Run

Jump n' Run is an Atari 2600 homebrew game I made over the course of 2016. It's a very simple platformer that features over 60 unique levels and 6 different enemies. The player must run, jump, and climb their way through each level in order to reach the end and beat the game.

It took about a month of my free-time to read an old copy of the Stella programmer's guide, figure out how the Atari 2600 works, and learn the assembly language required to create programs that can run on the 6502 processor. After that, I created an environment where I could quickly write code, compile, then test the game using an emulator. From that point forward it took another 8 months or so of free-time to develop the rest of the game.

In order to create level geometry quickly and easily, I developed a system that turned the screen into a very coarse grid (8x6) of level tiles that the player could collide with. It was by enabling and disabling these tiles that allowed me to create the many unique level layouts in the game. Enemy behavior had to be kept extremely simple due to the limitations of the Atari 2600 hardware. Enemies are only able to move in very basic patterns, such as linear back-and-forth motion or in a cyclical diamond formation. The level creation tools I designed are robust enough to place an arbitrary number of enemies within a scene. I also added the ability to control certain enemy variables such as the limits of their movement and their speed. This versatility became necessary to design fun and exciting levels.

Developing Jump n' Run became a very good exercise in efficiency. An Atari 2600 only has 128 bytes of RAM and a cartridge only stores up to 4 kb of ROM. This means I could only write about two thousand lines of code before I would bump up against this limitation. The 2600 handles graphics by directly manipulating the placement and the color of a cathode ray tube. It's an archaic system and requires a lot of patience and precision to use correctly. Despite these limitations I found developing Jump n' Run to be a really satisfying challenge to complete. It was an experience unlike anything I've seen in modern game development.

Jump n' Run is currently not available.

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