First, the bad: Could not tell what to do/where to go. Found a couple of tapes, explored the entire map, did not find anything of note. Had to eventually quit. Sonar does not appear to reliably lead you to any objects of interest. Really unfortunate, was greatly looking forward to this. I understand it was made quickly for a game jam though without much opportunity for play testing.
If you continue working on this concept, some proposed additions:
1. Ambient atmospheric life support noises
2. A robot arm for collecting the tapes
3. The sonar monitor doubling as a down-facing video feed using one of the buttons, maybe some other views to toggle between (up, left, right, rear, opportunities for spoops to appear on the monitors when this is happening)
4. Finite but generous O2 supply which visibly dwindles over time to furnish constant low level anxiety
5. Finite battery which also dwindles as you use it up, see above
6. Ability to surface in order to replenish O2 and battery (from solar) on missions in shallow water, but not deep water missions
7. Drop weights (which can malfunction for a few spoop moments)
8. Increased variety of marine life (Obviously you did not have time for this, even the whale was nice though)
Having said all that, some well deserved praise: This control scheme rocks for a submersible game. Piloting the sub while simultaneously being able to look around inside it to operate the controls, I mean. I'm shocked I haven't seen in done in any big budget games before.
It'd also work very well in VR, looking around with your head, reaching around to push buttons/flip switches with your own hands, some spoops happening *inside* the sub itself. Like when you turn around, after perhaps seeing a moving shadow on the wall of the sub to one side, or hallucinations where there's another bubble window behind you, very fertile concept for horror and very intuitive/capable mechanics!
I would very much like to see this expanded into a full game with expanded mechanics and modernized visuals, especially if it supports VR. It's got a lot of untapped potential, there's nothing like it in the horror space to my knowledge.
I wrote the in-game dialogue and consulted on marine technology details for Narcosis, a well received VR deep sea survival horror game, and would be happy to lend my talents to such a project if ever you felt inclined to move in that direction.
I think people use sonar initially, because they think it's a exploration horror game. Where the objects are hidden until they bump into it, like how slender the 8 pages was. Also I think some people don't realize their being given the coordinates under the tutorial prompts. I know it took me a few seconds to realize those were coordinates.
Amazing game as usual though!! I know I loved it.