I like the buildup and think has that "theme" music structure and progression you were aiming for. Sounds good, too. I'm not sure you should have ended on such a "sad" chord, but what do I know? I think it would work great fleshed out to a more "song-sized" arrangement.
BIAB 2019 Audiophile. Windows 10. Former user of old version. Prefer creating while learning over learning before creating. Passable, intermediate level acoustic rhythm guitar player. Songwriter, lyricist, composer loving all styles.