Hey @jkulawik, thanks for reporting your findings and kind words,
You are correct with everything, just to respond to a few points:
Circle to crouch (why isn't Dpad down used for this?) - I felt pressing d-pad to jump/crouch and simultaneously using the very same d-pad to move left/right is awkward, the way you have to position the thumb to access two buttons at the same time, but for most of the time I test SpelunkyPSP on desktop while developing so my experience with PSP controls may be off
Taking the golden idol didn't trigger the boulder trap - Not implemented yet
Music doesn't loop - doesn't loop in the original game either, I was thinking whether this is intentional or not at the time of adding music (the theme doesn't loop in a seamless way), still don't know, but probably should loop it anyway as you pointed it out
Will leave the issue open until I post a PR with corresponding fixups.
I ran the game on my PSP 1000. Here are some issues I had, maybe you will find it useful to know about them:
Input documentation would be nice, I wrote down what I was able to figure out:
Asides from that, amazing job, it's very nice to have this game on a PSP, and in such a small file size too π