Hey Sayu, thank you for trying out our game!
I am actually working on the collisions today ^^ . I think it has something to do with the tile seams, so gonna try to fix that when I can.
We didn't really have time to get into the story, but it has to do with the other person in the thumbnail. We already planned it out for the most part and will work on that in a later update.
Thank you for the feedback!