This seems inspired by the alchemist game that went pretty well on Steam (can't remember the name). I think it doesn't fit really well with the theme, but still a pretty a good game!
I'm not sure what game you're thinking of. The basis of the idea was playing as two different characters of different sizes, working together. I think that the larger character (Al the Alchemist) being in first person made that not super obvious though.
I got it that one is a mice and the other is a person, so different scales. But in the game play it is not really important that they have different sizes. I would have liked more a game where scale mattered in the gameplay itself, but it is just a matter of tastes I guess ahahah
