I absolutely agree about the lack of variety, although to be perfectly honest that's sort of what I was going for. At some point I did have one or two other "obstacles" that could generate between the "caves" and would eventually spawn with them as well to add variety, but I simply couldn't fit them in my development time.
That game breaking bug unfortunately took a lot of time away as well. I spent much of the last few hours before submission trying to find what was causing it. Pico8 unfortunately doesn't have much going for it when it comes to debugging, so I was working with what I had, and regretably I fell short. Funny enough, this bug took away the time I would spend on making the level generation a little crazier as the levels progressed.
I do hope to fix it all and update later once the jam scores are done! Thank you for playing and for your feedback! I really appreciate it.