You just started? And made a game in SDL?? This is awesome, like really. Hope you learn a lot in the future. I liked the game and played it for a good while. got like a millionish score. the orbs do little to no effect as far as I can see to be honest. I think you should make stronger upgrades because in the end I just died intentionally to write you this review.
I also can't really point how the enemy AI works but im guessing it rotates in some direction when the player is moving and when the player's still it goes towards is, which IMO makes it very dumb. kinda like its avoiding me when I move a certain way yk. but overall Keep the good work. I'm sure with some little upgrades I could play this for HOURS.