This is a fun and cute game! However, when you reach the surface, there's this certain section (above where you first enter the game) with a pit and two gems floating in it. After falling into the pit, I realised there's no way to get out; there weren't any ladders or secret passages to crawl through. I can't tell if this is intentional or if there's another way to escape that I don't know about.
Actually, I'm playing the game again right now, and I just discovered you can jump down through certain platforms. When I'm on the surface, these platforms sometimes aren't visible, but I remember the location of these platforms and am able to jump through them.
I don't think my first playthrough of this game had a softlock, I just didn't know about some of the mechanics of the game yet.