I really think that you should print t-shirts with Leo the cat on them. The character is amazing, he reminds me of Pepe the frog, who means "HOPE". I have no idea why Leo hunts the butterflies (maybe he is an well-known entomologist, PhD), but he really is charismatic.
One interesting thing that you could improve on usability has to do with which keys you assign to which action. Think that if two actions could be done at once, but they are performed with keys that are pressed by the same finger, that will create a conflict. This was my case with moving tight (D) and using the net (E). You may use the net for a button that is presses with the right hand (for example J), leaving the player the choice to jump (Space bar) with the thumb he prefers.