I really quite like the concept of the game, the switching between the two characters is a really interesting mechanic, but I think I failed to follow along exactly how the two different levels interacted with one another, and I might have accidentally cheesed a section? I got to a point where Seal was in a room with four runes and a blocked door, and Mouse was at a point where he had to seemingly impossible jump. I tried different things but ultimately was stuck and unfortunately wasn't able to finish the game.
But I really think there's something interesting here! You've gone in a super unique direction from the theme for sure. The game is undeniably teeming with personality.