Sunday Funday: this track reminded me a lot of the old Wii and 3DS menu music! It has that calm, animal-crossing vibe to it... perfect for the story point you are trying to convey.
A world of my own: Smart use of the bubble popping sounds to actually tie in the image and the story into the music! For me, I used scribbling noises throughout my soundtrack to convey the doodled fish at the bottom of the picture. Attention to detail like the bubble popping sounds is what distinguishes this from any other synth pop track.
The Nurse Told Me To Be Good And Come Back Tomorrow: I appreciate the emotional affect of this piece. I don't want to say it left something to be desired, but I almost wish there was a more contrasting b-section, perhaps with different chords, to show the depth of the emotional impact this would have had on our main character.
Mommy's A Liar: this superficial, evil-sounding melody is actually perfect: it's not truly evil, but just a fantastical evil created by the mind of the girl. This track also would have benefitted from a more active rate of change. It's largely comprised of one bassline and one percussive countermelody. Perhaps introduce the countermelody sooner, then add a b-section with entirely new material? (Loved the heart monitor at the end-- between that and the car engine sound used earlier, and the bubbles, you're doing a good job of bringing the game material right into the soundtrack.)
I love you, mom: short and sweet. What a sentimental story, and this ending didn't need to be anything but pastoral and melancholic.
Your concept for the visual novel is very fitting for the artwork, and one of my favorite interpretations so far. Great work, and keep writing!