Hey man it's Z, just commenting a list of suggestions to build on the core concepts of the game.
1. I feel like the there could be more visual interest in the background, be it animation or a Parallax scrolling effect for different levels of the scene
2. I think there could be more enemy variety, with different sprites and mechanics ( as well as incorporating the birds as an enemy to add more strategy in avoiding the ground enemies.
3. Maybe put in boxes and thing the player could jump on top of to give them more height to reach other things
4. More collectables, potentially powerups or things to increase main currency collections
5. Maybe a button that can take you to a store where you can buy cosmetics and upgrades with the in game currency
6. I think it would be nice to have a button to exit the game instead of using the ALT - F4 route
7. I think the art style can be revised so all the assets feel like they come from the same world
8. I think the music could also be revised, it needs a lot less reverb lol
9. I think the running mechanics can be a bit more tight, I actually really like how they push each other around and think that mechanic could be explored further
10. I also think the player and enemy sprite sizes could be adjusted cause they look a bit small compared to how much space is left on the screen. (though this also can be helped by filling up the space with other things, though it all needs to be balanced)
Over all these are merely suggestions to add to the base game of which you've done a great job at creating.
U should be proud it's a fun game and all u can do is make it better!
Super keen to see what u make next.