Really cute first track, it does the job and the theme is really great but it become really repetitive and the lack of variations is the main issue.
Cavern looks really minimalist maybe too minimalist. The main melody is too far.
The king got goofy vibe i like that a lot x) some crazy king ^^
Octoking is interesting, and great ideas.
Last track is nostalgic but the transition isnt really smooth and kill a bit the mood.
Overall i think you will benefit of a better mix.
Thank you for your work :)