Galactor released for NES (Game Genie Mini Jam)

Galactor is a simple NES game that fits the harsh limitations of a Game Genie cartridge: limited scope and very blocky graphics.

This is a simple shoot'em up. Shoot with A (you can hold it down for continued fire) to stop all the enemies before they get you.

There are 4 different types of enemies to destroy or avoid:

• The Red spaceships are flying by, shoot them to earn points: 1 point per hit, 10 points per kill.
• The Blue spaceship will try to hit you, shoot them first!
• The Yellow spaceship will chase you around the screen until you destroy it.
• The Yellow/Red satellite is invincible and can deflect your lasers. Avoid it at all costs!

Looking for challenge?

My current record is 966 points, can you beat it?

About

This game was made in about two weeks for the "Game Genie Mini Jam" hosted by lidnariq on the NesDev forums. The goal of this jam was to make a NES game that could run on the very limited cartridge PCB used to build the Game Genie device.

Basically, the whole game code must fit on a 16kb ROM, and the CHR (graphics data) is limited to a very blocky set of 16 predefined tiles that cannot be customized.

To be more specific: the game can have a maximum of 16Kb of code, basically the size of the very first NES releases from 1983-84. This is small, but doable.

The real hard constraint comes from the graphics side. In regular NES games, you can draw your pixels like you want and use up to 3-4 colors per sprites and background tiles. But the Game Genie is much more limited: it uses a fixed and predefined tileset composed of a grand total of 16 different tiles in total. They are used for both sprites and background. Those tiles are very blocky: each "pixel" of the Game Genie tileset is actually made of 4x4 pixels on the NES screen. And those tiles can display only one color at a time!

So basically, the NES is now limited to output graphics more limited than an Intellivision or Atari 2600: low resolution (64x60px), single color tiles, 5 colors in total for background + 4 colors in total for sprites.

I really loved this unique Jam theme, and decided to make something for it. The limitations were challenging, but I had a lot of fun creating something within those tight constraints.

Last but not least, the catchy music is not made by me, but by a talented musician named B-Doh. The track is titled "Fire Song" and available under a Creative Commons BY-NC-SA licence.

An open source game

The retro games homebrew communities are wonderful places where people create new games for old consoles for the fun of it, and love to share their work and knowledge with others. So whenever I can, I try to contribute too by documenting and sharing the source code of my games, hoping it may help others to make their own games.

In addition to the ROM, you'll find a zip file containing the fully commented source code of the game. As detailed in the README inside the zip file, the source code is released under the MIT license, and the assets (graphics and audio) under a Creative Commons CC-BY license. The game was programmed 100% in C using the wonderful CC65 toolchain coupled with the NESLib, NESDoug and Famitone 3 wonderful libraries. Please don't hesitate to ask me if you have any questions about the source code or how the game works.