Great job! Cool idea, especially as a side scroller. Bellow are some suggestions and bugs.
Things I would add:
-Player animations.
-Enemies.
-More food throughout the level.
Things I would improve:
-Add a narrated auto-scrolling intro with more legible font.
-Matching sprites (ex: the background is *very* pixelated while the player and obstacles are less so, and all the textures are generally mismatched.)
-Add story elements (signs or NPCs).
-Make the screen follow the player. (The player is locked at the bottom of the camera's view which makes it hard to see the ground when jumping.)
-The health and food bars are "blurry" and look stretched. Maybe made a custom sprite for it that is made at the right size.
-Maybe add a visible barrier above the "wooden tunnels" instead of an invisible collider.
Bugs:
-Jumping is infinite which results in being able to jump very high.
-Colliders on the grey brick pyramids are wonky.
-Part way through the level, the background has a black line through it and it is mirrored after that.