Yeah this is a good concept that you can go places with if you want.
If you do keep building to it, there should be something interesting to find at each new depth. It could be anything. Enemies, items, lore, different environment, whatever you're into. But that is what would keep players interested in going further down.
Viewing post in Arctic Static jam comments
Yeah, the original concept was to "uncover the true reality of that place" to go with the Under the Surface theme, being more of a mystery game, but I ran out of time and had to rush the progression a lot after getting the main mechanics and presentation down. There was also a temperature mechanic with a heater and battery, sea currents and a turbo boost to push against it...
But yeah, the progression is the weakest part of the game because is the last thing I did, but so is the life of a jam game. I'll see if I polish this further, thanks for the feedback!