Depth Hunter is a very basic first person underwater diving simulator. The game is build around three simple core mechanics, shooting fish with your harpoon and then towing them in with a line (Zelda-style), searching for treasures and making pictures. The campaign mode of the game, which is around three hours long, is simply a series of those core mechanics strung together, there is no effort made to construct any kind of narrative, even in the most basic sense.
The controls are similar to FPS controls, except with a third dimension adding, left stick lets you move forward, backward and strafe to the side, while the right stick lets you look around. Movement is very slow and looking around has a certain amount of sluggishness to it, as would be expect from moving around under water. A limited oxygen supply requires diving up to the sources for a breath of air.
The harpoon works much like your gun in a FPS as well, left trigger gives you a zoom, right trigger shoots. The reload times are very long and the harpoon is rather slow, so getting a good shot requires much more planing then in an FPS game. The fish also behave somewhat realistically, if you get to close, they will try to get away quickly, making it almost impossible to shot them, thus some patient is required to get close enough for a successful shot, but not close enough to scare the fish. Once the harpoon caught a fish it has to be brought back by moving the right analog stick in a circular motion, if to much tension is on the rope it will break, if to little it will get away.
Finding the right fish in the first place takes a good amount of the game time, as while the game will give a hint at the general location of a specific type of fish to catch, it won't show exactly which fish to catch, so one has to identify them by their silhouette, which works pretty good and is a good bit of fun.
Treasure hunting is probably the weakest part of the game, as treasures are just randomly scattered around the sea floor. There is not much reason as to why the treasures are there or any attempt at building a narrative by the kind of treasures that have been scattered. Treasures are also rather hard to see, so there is a lot of trial&error involved.
The photography aspect of the game is very basic, but functional. A campaign mission will instruct you to take pictures of specific fish or objects and then you just have to swim around till you find the object and make a good picture of it. Your camera has an indicator that will tell you when your are close to the object and when your shoot will register as success, so a little forward and backward swimming is required to get the angle the game wants you to make. Photos can also be taken completely arbitrarily and viewed in the games main menu.
The strongest point of the game is just the general atmosphere and the graphics. It really does look and feel like under water with all those fish swimming around, the slow and sluggish movement and everything else. It a very relaxing game to play and can essentially put you to sleep, in a good way. One little annoyance is however in the character design or lack there of, while some of the box art depicts a girl in a swimsuit, what you end up playing in the game looks more like a generic Navy seal, same for the boat, which doesn't exactly look like it's build for tourist either. The character is however only visible in a reflection at the water surface, as there is no third person camera and the boat is just meaningless non-gameplay decoration anyway.
The game features just three, not very big, locations that also happens to look very similar to each other. There is absolutely nothing done to give the game any kind of narrative or progress, you don't get new weapons, an oxygen tank or anything. The tools you have at the start are the same you use at the end, there is no upgrading or anything. While there is a lexicon that contains a page of text for each fish, the game does make no attempt to integrate that into the gameplay in any way. The treasures you hunt for are completely without context. A free swimming mode is available, but two of the three the scenarios in it have to be unlocked via the campaign.
Overall I enjoyed it quite a lot, the atmosphere is great and it's a good switch from the random run&gun game. But the overall structure of the game barely qualifies as game, it's more a tech-demo containing just the very bare minimum to provide some challenge. The game also has to many cop outs, sharks and manta rays just give you a "don't shoot" when you point at them and you can't interact with them in any way. Your boat is completely useless, as you can't interact with it at all. There is no way to feed fish or have more complex dives where one need to take more care about oxygen management or anything. There aren't any other divers or scripted events or anything that would break up the regular swimming. But either way, I had my three hours of fun with the title, not something I would recommend throwing any serious money at, but when you can get it cheap in a bundle, go for it.