I definitely see the potential with this one as an incremental game, but I feel that there are a few problems with the design:
1) There is no incentive to explore the game incrementally. You could go straight to the depths with the most valuable items straight away with no sense of progression. Perhaps upgrades that increase the depth you can descend to would be useful in managing this.
2) Progression is inconsistent. Early game low-value items spawning alongside the highest value items only found in the far depths makes the radar behave inconsistently and gaining money tedious. I would recommend phasing them out entirely as the depth increases.
3) Shark detection is difficult to predict and nearly unreactable. Some sort of warning or visualised detection range would probably serve the game well.
Other than those things, there are a few minor issues I noticed with the execution - the background music has a couple of notes that are much louder than the rest, the tractor beam sometimes doesn't pull items into the submarine even when not moving, and without any fore- or mid-ground assets to use as a frame of reference, the parallax in the background makes it very difficult to tell how fast and how far you're actually moving when there aren't any collectibles onscreen.
This is a very solid concept! With more engaging upgrades and communication of mechanics to the player, I feel like this would make for a comprehensively enjoyable game. Still, great work for a one-week jam!