Its well visually represented, although the gameplay of The World's Hardest Game tends to be more precision movement based instead of aiming and avoidance your game tends to have.
I do like how you replicated the level layout and mixed it a bit to be more zombie themed with darker colors and the chasing zombies. Though after killing all 3 zombies results in them getting stuck in their spawn point.
You can maybe add zombies that require you to have precise movement? Like them dashing occasionally so the player needs to dodge to the side or zombies with patrol paths.