I think the first handful of levels were very fun. I had a lot of opportunity to make my own decisions and find a playstyle that worked for me. The later levels started to feel like I was forced to play a certain way (again, I may just not have the skillset to see my options).
Here are a few videos that reshaped my thinking on level design. Maybe there's something in there that you find useful too.
Tips for open level design:
Your levels are essentially puzzles for the player to solve: