This month's Rust update truly is a whopper, introducing a refreshed underwater biome with procedural underwater lab dungeons, submarines, torpedoes, sharks and more.
The update, which launched yesterday, introduces procedurally-generated underwater labs to the world of Rust, which will come in a variety of shapes and sizes - but always with two entry points. They can be entered via a "moonpool" using a submarine (another new item that we'll get to later). The labs also have CCTV to help you plan your route, along with microphones that let you "broadcast your commands into the entire base's network".
Some labs even come with mess hall rooms that allow you to play high-stakes poker, or barbecue meat while listening to music with your pals. That all sounds relaxing, but there are also plenty of nefarious NPCs on board that want to spoil your day - best stay on your toes. You'll find some tasty loot if you make it past these puzzles and enemies, so perhaps the reward is worth the risk.
As previously mentioned, the update brings two new types of submarine: a one-person submarine, and a two-person submarine. Aside from the obvious difference in size, the two-person submarines also boast rudimentary sonar and internal fuel access - while those using the one-person sub won't have access to instruments, and will have to get out to fill the tank.
Both submarines do allow the use of torpedoes, however, with direct torpedoes that can be fired straight ahead, or surface torpedoes that rise to the surface "then speed along the top of the water". You can buy submarines and torpedoes from fishing villages, or simply craft the latter yourself. Oh, and keep an eye on your submarines, as they will decay if you don't keep them outside and unused.
Back up on the surface, the "handmade fishing rod" is now fully operational, and can be equipped with bait (such as worms found on various plants) to help you catch fish. You'll need to tire the fish out when reeling it in, but putting too much strain on the line will cause it to snap. The update also adds eight new types of fish "from Herring, Anchovy and Sardines to Yellow Perch, Catfish, Small Sharks, Salmon and Orange Roughy".
Something you might want to keep a little more distant from, however, are the sharks being added in this update. "Each dive site has a chance to spawn a shark which will patrol the area and must be defeated before you are able to claim whatever treasures found at the dive site," the update blog post explains. Melee weapons are one option, but the new Speargun weapon will serve you better: this can be fired at a distance, and crafted at a level one workbench.
The blog post details some further tweaks such as the improved underwater ambience and effects, along with more general improvements and fixes. YouTuber Shadowfrax revealed the update last month, and you can take a look at his footage here.