I like it a lot! Establishes a mood really well. Even the denser parts of the arrangement still have enough air to make out the distinct parts.
Swell and Fade:
The synth-flute(?) lead makes a nice through-line for all the different moods, from ambient to driving and back again. Really hits the story beats. The rave/hoedown in the 3rd part was unexpected, and maybe a little incongruous, but I'm not mad at it.
Sea Highway:
The almost-train beat in the intro threw me a bit, but the main drum pattern is nice. Creating the progression mainly by adding and removing layers makes for good traveling music, and keeps the loop from feeling too repetitive.
Ribbon:
Like the lead/bass synth mimicking the motion of a ribbon eel. The addition of the live flute tosses in some nice textural variation just before it starts to feel repetitious. I think bringing the flute out more in the mix might have made it feel a bit more mystical, but then again, having it a little obscured might add to the alienness of the Sky Eel.