the jump feels a little too low for the size of the tiles and spikes to comfortably be able to jump over them. the hitboxes of the spikes are in my opinion too big. it's normal to make things like spikes in games heavily favor the player. so and making making the hitbox of things like spikes smaller hitboxes for the player crushing enemys very large is normal. I also think it would be good to launch the player slightly upwards when jumping on the slimes for extra feedback.(I feel like i sound very negativ but im just trying to help)