The map feels a little empty, could have used some tree assets, other NPCs. The mouse animation is very subtle, at first i couldn't tell if it was animated or not, maybe having the ears or tail move would be a nice touch but not really necessary. Transitions to other areas are a bit abrupt, can be short but maybe with a simple fade in/out.
I really liked the design of the main character and the environment. Certainly there's always polish to be done but I think you have a great mechanic and cute art direction! The white outline against the character is such a small thing but I find it to make a big difference against the backgrounds. I like frog :) The music was lovely and the concept of making my own song after finding sounds (like Zelda?) is great! So much you could do with this if you wanted to!! Amazing job, really