This is great man! I Love it!
Of course like any jaded teacher, I have to say that the theory doesn’t matter as long as it sounds good. So not that we’ve got that out of the way:
The big thing here is that you’re going back and forth from a D major sound to a D minor sound, and the change from the F# to the F natural has a BEAUTIFUL dramatic impact. But there is a little more going on here that just that.
So another thing that’s going on here is that there is a parallel key change. The first chord is like a Dsus, or really more like a DM-GM; then the exact same key change to CM-GM. Another way to put this is I-IV in D Maj and then I-IV in C Maj. the part where you bend in the E to an F in the C Major part has that great dramatic effect of playing the F instead of the F#, so you played the MINOR 3rd instead of the MAJOR 3rd from the previous chord. This is a REALLY important thing to understand as the MOST important noted that define the tonality of a chord are the 3rd and 7th. So in this example, you established the tonality of D major, and then you hit us with that F natural and it twists our ears and implies D minor, which is a very different tonality.
Then you play something like a D Mixolydian with the notes F#-G-A and then the slide to C. Your lowest note is the F#, the highest C; those are the 3rd and 7th of a D7 chord. You also played the G natural, which is a natural 4 and implies the mixolydian sound.
It’s a bit difficult to describe of the internet through text, but you also implied the mixolydian sound when you went from D Major to C Major since the ONLY time a major chord is exactly 1 whole step away from another in the major scale is the IV-V chords. But the more important thing here is that your harmony works for a few different reasons.
THEN you play the V-i sound and go from that D7 to G minor, which created ANOTHER dramatic change since our ears were on D mixolydian which has a B natural, then you went up to the minor 3rd of the G minor with a Bb. Again, we had an established note and you changed tonality by emphasizing the 3rd of the next chord. Another great change in tonality, and a very stable one since you played off of the V7 and went to the minor i. Then you went from the G minor and treated it like a minor iv, back down and ended on the minor i.
So ultimately, you started in D Major and ended in D Minor in some really clever ways. Great job man! You’re really following what Syn and Papa Gates always say to do and “create your own weather”. You’re treating each chord as it’s own tonality and playing the notes to fit the chord instead of just playing in 1 key over the whole thing.
This has a bit of the “So far away” vibe to it as well as a little bit of a “Beast and the harlot” vibe.
Keep writing dope licks my man!