It's a nice start for a platformer I think but the collisions could really use some work.
The players and spikes colliders are larger than their sprites. This makes the player appear like they're floating and makes the collisions feel unfair since the sprites don't actually overlap or visibly touch. I think the player collider is a circle or capsule which makes you slide off of edges which isn't ideal. The end of the 3rd level is the most affected by the large colliders.
You generally want the hitboxes to be smaller than the sprite they're tied to, spikes especially so. I promise this doesn't make the game any easier. Look at silksong if you want an example. I've made a couple platformers too, so I'm not speaking out of my ass here.
If you worked on the colliders a little more I think you'd have a really solid start for a platformer tho. I've run into the spike collider issue in my previous games so felt like I could share some of my knowledge. Anyway good job on the game!
(i tried attaching screenshots but they're not showing up)