Well, I figured out what may have killed all of my 6 attemps at a first playthrough.

Just today I hit level 20 (again), re-unlocked the Frozen Wilds (again), saved and quit. Came back after lunch, launched the game, decided to go into the options menu, turned off V-sync and frame rate lock, and then changed my mind about V-sync, so I turned it back on. Upon exiting the options menu, I was asked if I wanted to save changes, so I said yes.

Started up the game only to find that I was back at Misty Lagoon, as if I was starting a whole new game from scratch.

This may explain why I lost my save games before, simply tweaking a setting in the options menu apparently resets the entire thing. What the heck?!

Secondary issues I am experiencing is that the sonar pulse will scan a nearby item, but not emit any sound at random intervals, and on entire dives, it will only seem to pick up threats and ignore any items. In the Silent Cove level, it is doing this very frequently. Sometimes restarting the game will fix it, sometimes it won't. Also in the Silent Cove level, the sonar will sound off like it is finding an item when there is no item to be found- there was a paritcular wreck that this was exhibited near, even after I cleared out the entire area and left no netting or other destructibles behind.

In the Deep Forest level, in the Tunnel Network section, I verified that I harvested all mineral deposits, but the game kept saying that I was missing one.

Very frustrated with this. Advice would be helpful. I don't think I have the stomach to start ths over yet one more time knowing that I could lose everything again. Otherwise its a pretty neat premise for a game.

Thanks-