It was quite hard for me to figure out how to do the wave surfing properly. I think a big part of it is that it's quite difficult to see when the slope starts going up, especially since the slopes are constantly changing. I eventually managed to fly long enough, mostly by judging based on camera angle. But I would still randomly misinterpret a wave's slope and slow down to a crawl (i.e. it was hard to consistently fly). Maybe if I had more clarity on when I was speeding up and when I was slowing down, it would have helped?
Then, I wasn't entirely sure how to destroy towers. I think you just sort of bash into them, but that doesn't always work, so who knows. I eventually got one of them, and it told me to go save a friend, but I spent a couple of minutes looking and couldn't find them. The towers had those green beams of light, but I couldn't find (or missed) the equivalent for the friends. So eventually had to quit it there.
I'll say that when the mechanics worked, it feels really nice. I'm wondering if being way more lenient on speed reduction would make this better; i.e. making it easier to do the thing that's fun. At least initially. But there's also something to be said for feeling like you're mastering the skill, so maybe not.
Anyway, nice job.