This looks nearly identical to Ink, an indie game already on steam: https://store.steampowered.com/app/385710/INK/
It's impressive how two people can stumble onto the same idea.
Viewing post in Only One Rectangle jam comments
I've beaten Ink, and it's pretty fun. After playing this game, I found that it's basically a less polished version of Ink. No major differences in gameplay, mechanics, or art style.
Like I said, it's interesting how different people can come up with nearly identical copies of the same idea. (Like Newton and Leibniz both discovering calculus)