It is snake-like so you could play just like a normal snake game.
But please don't! In this game, you have to act like a spade to dig the seemingly meaningless super thick "walls". After that real food will be spawned and you can eat it to earn points.
Two players can battle with each other under such rules. Take the best strategy for you: safely accumulate points, take risk to earn more, disturb the board or chase your opponent... and avoid sudden death.
Itch.io link: https://yarray.itch.io/spades
Some screenshots: