Sounds great! Captured the feeling of exploring an ancient lost ruins very well, and I enjoyed how it switched things up as it progressed but still flows naturally. Great use of instruments and synths to help enhance the ambience.
Some critiques I have is that maybe there could've been a little extra mixing to the sound, though I can't say exactly what. Probably some extra EQing in the mid-range. I also noticed something sounding a little dissonant with the low bass, like something is overlapping it when the key change occurs.
Other than that, I enjoyed this. Great work!