Thanks, glad you enjoyed it! The harpoon mechanic turned out a quite glitchy in the end, but the only difficulty with catching them is that your line breaks quicker. There may have been some hit detection issues; I'm not sure why you had to harpoon them twice
As you dive deeper, the only frames of reference are the oil rigs in the background and the depth gauge. Working in that scene for so long, I think I got a good sense of where I was quite easily, but I can see how it was disorienting. Regardless, I hope it didn't interfere with the core gameplay.