If Agumon came with a Digivolution gimmick and a bar to fill up, I think it'd be interesting if Agumon getting damaged actually drained it. It's not good petcare to let your v-pet get harmed.
I actually love this kind of idea; though I take it one step further. Just being Greymon drains the gauge, and if you don't spend time as Agumon voluntarily to refill it you'll exhaust the poor dear and revert to Koromon. (Because obviously we can't force your Digimon back to an egg during the match... although Yoshi does mean that mechanic exists.)
My idea for balance is giving them a Monado Arts like set of evolutions. Greymon, GeoGreymon, Growlmon, and Tyrannomon would all be reskins of each other, but with different stats and different breath weapons. Coredramon would be almost the same BUT with wings that would have to be animated, because it is the form that grants a multijump
I don't know if they'd do all of that, but Nintendogs is an interesting connection I hadn't made. They could use the Nintendogs stage for some Digimon spirit battles...
Right, my apologies, I was moreso trying to give an idea of the rich level of material there.
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UNRELATED, ADDED VIA EDIT TO AVOID DOUBLE POSTING
I have a silly idea for Classic Mode for Agumon that I really like; but I need help from you guys to complete the idea!
You and your opponent's are in stamina mode with health constantly decreasing; but food keeps spawning on the stage. It's a competition to be feed. Your opponent's represent other V-Pet games.
Some of the characters will represent their own series because they have V-Pet spin-offs. These include Pokémon, Pac-Man, and Sonic.
- Pokémon will be Pikachu with a respawning Pokéball Eevee.
- Sonic would have three mini versions. One would be regular, metal, and one would have bunny ears and a Tanuki Tail. These are all references to different Chao appearances.
- Duck Hunt Dog would have to be there too, as the Nintendog.
- ???
- ???
- BONUS STAGE
- After that he fights a hoard of himself in a normal match. This time on his home stage.
- After this he goes up against that dragon from Monster Hunter, but with all the other V-Pets fighting with him. Unfortunately they are all programmed to die pretty quickly, leaving Agumon to fight on.
Ideally the title for this campaign would be: "Agumon, Digital Monster. Agumon is The Champion."