Other than the bugs others have mentioned, the game feels polished and complete, which is huge for a game jam. The music selection is nice, the Text Animator you used is charming, and the animated rainbow effect on the title of the game just made it all feel overall better to me, even if it wasn't directly linked to the gameplay.
Gameplay-wise, it felt alright. I never felt the central gameplay gimmick of touching the echoes disabling your movement controls; they were too far to the left to ever come into play, and even if I did go out of my way to touch them, it didn't seem like anything happened. The echo balls colliding with eachother did intrigue me, though; part of me wonders if there's something to explore with making the shots bigger and slower, such that colliding with the enemy shots occurs more frequently, which could potentially be exciting/interesting to play around.
Regardless, this is solid for a first attempt!