cat.png by Shepardskin https://opengameart.org/content/cat-sprites
mouse.png by peony https://opengameart.org/content/cats-pixel-art
cheese.png also by peony https://opengameart.org/content/breakfast-pixel-art
crate.png by devnewton https://opengameart.org/content/crate-tile
planks.png by Lil Pie https://opengameart.org/content/planks-floor
input.png by qubodup https://opengameart.org/content/mouse-buttons-arrow-keys