Hell yeah, a groovy song. As soon as it starts, I'm treated to a steady rythym.
It's harmony is pretty good too, it captures a perilous, threatening feeling as well as brief hope in other parts. I can imagine it playing over a crystal obstacle course.
This one immediately captures both crystal and castle. Most of the songs I've heard have this problem where they struggled to combine the two, and balance them. This one has no such issues. Strings and to capture the castle-y-ness. And the the reverby crystal sound for the crystal. As well as harpsichord, which kinda covers for both now that I think about it.
If I were to criticize it, I would say, that you could have modified the crystal with more reverby sound, and more overlaying crystal sounds to picture the castle as this massive sprawling and sparkling space. Or maybe to include more orchestral instruments, to portray a more royal vibe. But maybe that isn't what you were going for.
Great work. 👍