I understand the gun can build up momentum over time, and I do think it would benefit from doing that faster overall, but what I mean is that the instantaneous control you have over the character is far greater in jumps/wall jumps than it is in deciding whether to move horizontally and which direction to go. Perhaps once you know the levels you can just bounce around and never have to readjust, but, for learning them, vertical sections are a lot more wieldy and give you more to work with immediately. If blasting through with momentum is the intended design, maybe you could have the gun equivalent of a spin dash?
Thank you for your interest! Maybe I'll have the demo done by next Demo Day.