Dave the Diver (character) is a bit out of practice, but he's an easygoing sort and it doesn't take much to convince him to get back in his flippers to look into the local anomaly at the behest of his arms dealer "friend", who would be clearly bad news even if his name wasn't Cobra.
Said anomaly fills with new sea creatures from all over the world every time it's visited, and possibly building-sized terror beasts and ancient merfolk, but Cobra's sure it'll all be fine, so in you go, mate. It's certainly pretty down there if nothing else, and Dave the Diver (game) is, if nothing else, a rare game that makes the usually tedious water level a bit of a treat to wander round in.
It's a bit of a shame your main means of interaction is spearing every fish you can, even if they tend to get more aggressive the deeper you go. But I can hardly pretend I didn't enjoy hauling back heaps of them to the restaurant.
At the end of each day, see, you take your haul back to Bancho Sushi, a restaurant run by a guy who takes his cheffing just a little too seriously. You set the menu, balancing how many of each fish you have vs how much they sell for, and then the customers wander in for a few minutes, and you'll hurry about the bar bringing orders, cleaning counters, and pouring green tea. It'll be familiar if you've played just about any restaurant game ever, but the difficulty lands just below a stressful level.
The diving parts can be more stressful, as any contact with a puffer fish or anemone or assorted grumpy sea lads quickly depletes your oxygen, often several times in a row as your weapons are slightly cumbersome. Its roguelikery manifests as the layout and inhabitants shifting each time you dive, and as most equipment evaporating when you leave the water, so anything good you find will get very limited use, and you'll do well to get the hang of the basic harpoon and knife. It does lead to some of those annoying situations where, for example, you find out that the baseball bat makes you drift forwards and take a hit, potentially screwing up your run and losing you the bat anyway. But you can find blueprints for weapons by opening chests, then pay cash and resources (also found fairly generously underwater) to unlock them as starting options. It's all more forgiving than it seems on your first few days. A bad dive robbing you of all but one item may feel harsh, but quest items stay, and at worst it's a night of low profit at the restaurant.
I don't like the "90s olympic game" thing of hammering the spacebar or pressing alternating buttons very fast, but again, I kept doing it anyway. Bancho's great little martial arts style animations when he "enhances" a dish, the happy little diners, and the endearingly humble "cooksta" app updates give the game a sincerity and general goodwill to Dave the Diver (both character and game) that pulls it all away from anywhere mean-spirited or taxing. I don't quite love it, but it's close.