Ingenious Developer Fits Solitaire Game on Single Nintendo GBA e-Reader Card

In an impressive feat of digital wizardry, indie developer Matt Greer recently shared a blog post and a YouTube video that showcase his unique accomplishment: cramming an entire game of Solitaire onto a single, custom-made Nintendo e-Reader card. This card, noteworthy for its mere two “dotstrips” each containing 2,192 bytes, holds just over 4.3 kilobytes of data in total.

For those unfamiliar, the Nintendo e-Reader is a peripheral created for the Game Boy Advance. Initially launched in December 2001 in Japan and following in September 2002 in the U.S., this device allowed users to scan cards to play full games or access expansions for Game Boy Advance titles. Its storage, a notable 8MB, was a gateway to various gaming experiences. While NES ports could require up to 10 cards, and the system could handle a dozen, certain features, like extra levels for Super Mario Advance 4, were sometimes accomplished with just a single card.

The Solitaire e-Reader project goes into striking detail in Greer’s blog post, diving deep into how he developed this homebrew version of the beloved card game. By crafting a game under such tight technical constraints, he has ventured into a niche so unique it borders on the extraordinary. The world of homebrew Game Boy Advance games already caters to a small audience, but creating a Solitaire game that runs on a single e-Reader card is truly a rarity in itself.

According to the blog, the e-Reader can handle various kinds of game data, including NES games, raw binaries, and even Zilog Z80 binaries. This project took advantage of Z80 assembly thanks to its minimal resource requirements. The e-Reader also offers an API (ERAPI), which helps by providing access to common functions, reducing the need for repetitive dotstrip coding and consequently saving valuable space.

However, the Z80 emulator within the Nintendo e-Reader isn’t perfectly accurate. It only recognizes a limited set of opcodes and registers, meaning some operations typically possible on a Z80 simply couldn’t be executed on the e-Reader. Despite these constraints, Matt Greer managed to develop a fully operational Solitaire game, complete with changeable music, in just 4,384 bytes. That’s dotstrip magic at its finest spread over two strips on a solitary e-Reader card.

It’s regrettable that the actual e-Reader cards were only produced for a short window of time. As a result, the Nintendo e-Reader has largely faded into obscurity. Nonetheless, Matt Greer’s remarkable achievement stands as a testament to what homebrew developers can accomplish even with the most limited of tools.