Baking your thoughts into the video is genius - I wanted to do a retrospective of my own but this idea is way better.
These are faithful chiptunes - I dig the choice of waves and patches used. Composition and melody-wise it is on point - I can easily imagine these being used in a variety of games from the NES-era. I'm particularly fond of the main progression in Castle.
Kicking off Transition with the standard sound we've grown used to up until this point and then taking it literally by changing over to a more FM-based, modern sound was really clever. Seamless enough as well - not a jarring change, but a welcome one. Having this methodology stick for the remainder of the soundtrack is a great idea and does wonders for varying the soundscape.
All in all, great work - solid pieces here! Enjoyed them a lot, and that bonus track was pretty great too; intro progression reminded me somewhat of the early Silent Hill melodic tracks.