I openly admit that I've never heard of Shadowgate, but hey, I'm not going to turn down the chance to listen to live piano!
This is a pretty cool piece - while I don't know what the original sounds like (I should look it up!), your version of it strikes a great balance between mellow background music and a sense of conflict/urgency to come. I really like what happens with the phrasing around the 1:30 mark, where the accompaniment stays the same, but the accents/emphasis in the melody create the illusion of altering the meter. I saw that you said you frequently play each part separately - regardless of whether you're lining up the individual parts in editing or trying to get your two hands to do wildly different things at the same time live, it's not an easy task, but you'd never know that from your performance! Nice work!
Edit because I forgot to ask a question: just for curiosity's sake, are you reading music or do you play by ear?