Alright, this is one of the games that was overlooked while in an attempt to cash in on monster breeding game crazed.
Basically, it was robots battling robots, though they were innovative in creating a lot of game features the reflected later pokemon games.
The gameboy color cartridge ver. of the game included a real-time Day and night system, you could upgrade your robopons strength with a simple tv remote, and the cartridge itself had a speaker to notify gamer's when something went on in-game while the system was off. Example, in the game, you own a robopon company and have a carpenter. You pay him to upgrae the company building, but it takes roughly 30 minutes to a hour to complete the expansion. If you turn the game off, the carpenter will still be building; when he finishes, the cartridge itself will chime.
This is also the ONLY known GBC game where you can replace the save game battery [when its almost dead] and still keep your data! All you need is a Phillips screwdriver.
The battle system and evolution system was a bit one sided, though how you equipped and used skills or weapons to their full extent was interesting.
When the game moved onto the GBA platform, they updated a lot things. Sunny is able to evolve [My fav red punching robot]. You could change the color to your robopon and forge brand new ones. the battle system was also completely redone, though its not the best, its VERY playable.
Another downside to the GBA version is the story, its hard to follow sometimes while other times its difficult to progress through unless you ask around town to get better information to what you need to do next.
They stopped production after the GBA title hit the shelf, but I think to this date, it could have still gone a good, decent distance before dying out. Whats everyone else's opinion?