LETS. GO. Comprehensive Guide:
First section: Slide just after the second pipe in the background and hold jump to skip the two jumps, and then hold jump again to skip another jump
Literally everything else: Spam slide and jump only when you have to and when you jump make sure to follow that up with a slide IMMEDIATELY.
All that should get you 15.66 if not better :D
Overall great game, spent way too much time trying to do this.