The 4/4 theme is awesome, really. It has a Megalovania from Undertale vibe without plagiarizing it.
Melodically, both 4/4 themes are excellent.
However, since I like you and think you're capable of doing incredible things even in a short amount of time, I'm going to take the liberty of criticizing the 6/4 part: the melody doesn't breathe enough. The rhythm is too similar in each measure. In 4/4, you do three measures with the same structure, and the fourth gives it some breathing room and restarts the loop. Surprisingly, you didn't do that in 6/4. I feel like the melody is more intellectual and that you tried to fill up the 6/4. Am I wrong?
Otherwise, the 5/4 in transition mode is great, the tempo halved works very well.
And your transition sounds are used more sparingly.
Despite my criticism, believe me, I really like it and I'm impressed by the quality you've achieved in such a short time. It's a real talent!