I'm getting close to the end of this one. There was some meandering to figure out where to go. Got the depth charges which then led me to the light to explore the bottom of the sea.
More recently I found the radar so I've been gobbling up all the upgrades. Towing them from the bottom is a chore. I'm still missing a few tools. Where could they be?
Also, turns out fighting those boss creatures lets you equip more stuff at one time. The fights are tough! Missiles have been doing the heavy lifting to win them. Wait, wasn't I using stun torpedoes? If these can blow up rocks I think they would be harming the animals.