Wow, thank you! 'Wonderfully composed' is a great compliment, and I'm very grateful for it :)
And indeed, this is my first time using seventh chords. I used to think that they didn't have a purpose other than to make a song sound more "dissonant and ugly". I do not agree with my old self anymore: I think it depends a lot on the type of seventh chords, how they are voiced, and how harsh the instrument playing it is! In the past month I've read a ton about the different types of seventh chords and I am just starting to find out how to use them all :D