I've leveled up my 1st character for almost infinite $!
Was that a good strategy? Idk but it worked for me :P
Great art style! And awesome idea.
I would change the swapping between pets mechanic.
Instead of arrows I would love to have sth like an inventory/album/list o pets I have.
And for the Input/Output text it would be great to have an icon of what it its next to the text.