Thanks :D If you want to check the shadowing you can look at the code here : https://github.com/Sharundaar/wasm4-gamejam/blob/73cd70a83dd46c4d3c86b4c6b9c2a92...
It's heavily taken from : https://medium.com/the-bkpt/dithered-shading-tutorial-29f57d06ac39