|Publisher||Vast Fame (?)|
|Developer||Vast Fame (?)|
|Console||Game Boy Advance|
|Engine||Digital Monsters 3; Digimon Pocket|
|Sound engine||Smilesoft (Keitai Denjuu Telefang)|
|Alternate names/hacks||Digimon Rury|
The plot loosely follows the first arc of Digimon Adventure 02, with several changes.
The story centers around Dafu (Davis/Daisuke) from 02. During the school picnic, Dafu gets transported by a portal to the Figures world (Digimon world) and has to find a way back to the Human world while uncovering and putting a stop to Wild dragon reform's (Digimon Emperor's) plan along the way.
The sound engine is stolen from Smilesoft's Keitai Denjuu Telefang, rather than Capcom's Mega Man series. No specific company is credited in-game or on the boxart, but this RPG shows a few signs of being developed by Vast Fame.
- Much of Digimon Ruby's soundtrack is recycled from several games that are heavily associated with Vast Fame. Two battle themes and two overworld themes are from Devil Island while one overworld theme is from Digital Monsters 3, both of which have appeared on several Vast Fame multicarts. The ending cutscene theme is from Zook Hero Z, while one battle theme is from Zook Hero 2, one overworld theme is from Shi Kong Xing Shou, one overworld theme is from Shui Hu Shen Shou and one overworld theme is from Crazy Richman 2. All of the last five titles are confirmed Vast Fame games.
- The characters' names in Digimon Ruby are similar to their names in Digimon Saphire for the Game Boy Color, which reuses all of Crazy Richman 2's soundtrack. The names of the humans as well as the Digimon appear to be based on romanizations from Chinese. For example, Daisuke is called "DaFu".
- The battle system is recycled from Digital Monsters 3, as are some of the attacks and status-altering moves.
- Much like Digital Monsters 3, Digimon Ruby also has some of the creatures miscolored.
- Most of the creatures' battle sprites are recycled from Digital Monsters 3 as well as the GBC Digimon Saphire.