Legacy: "The Nexus"
Scenario: You enter this level many times and from many directions. This is a major crossroads where you can choose from several directions of travel. Also, the Nali village has merchants that will each sell you their goods in exchange for a Nali ruby apiece.
(If you are entering the Nexus for the first time...)
Nexus 1: If there isn't a Nali waiting for you as you drop down from the drainpipe, restart the level to make him reappear. He has to open a nearby area for you to continue.

(If you are returning from the Courtyard Stronghold...)
Nexus 3: This is probably the best time to clear out all the nasty creatures in the Nexus. Pretty much all that you'll find are some Scorpions in the cave entrance, a few Skaarj Troopers around the portal and the entrance to Triaxia, and one or more flies in random places. You really don't need the creatures lurking around, and the Skaarj Troopers will give up a little ammunition as well.
Nexus 4: Now that you have the Warp Key, you can use it to explore a little more of the Nexus. You will materialize on a high ledge, and there will be a very nice store of items nearby. You can use the Warp Key again to return to your original location when you're ready. Experiment with the Warp Key in other levels too. In some levels it will take you to a specific place and then back, but in other levels the key is used to mark a location that you can return to at a later time. I will mention in all relevant levels what the Warp Key does each time.
Nexus 5: If you're wondering where to go after returning from the Courtyard Stronghold, I want to remind you about the signs in the cave you first entered. There is a reference to a Nali that hides the keys to the White Palace and the Tower of Elijah. I suggest you follow him into the Forgotten Caverns. Also, you might want to pick up a Superhealth before you leave the Nexus, because you will have something that makes them unnecessary by the time you return.
(If you are returning from the Altar of the Sun...)
Nexus 6: When you decide to get down off the ledges that you are on, return to the area with that portal and look for a small body of water on the ground near one of the ledges. It will be deep enough for you to land safely.

Nexus 8: The Nali in the manta's nest mentioned a new weapon being developed by the Skaarj. Going after it is definitely a dangerous idea, but it may be worth the risk.
(If you are returning from Triaxia with the Skaarj weapon...)
Nexus 9: You should know that you caused a major commotion in Triaxia when you stole that weapon. There are quite a few Skaarj Warriors waiting for you as you enter the Nexus, so be ready for a long battle. Oh, and try not to do much of your fighting in the village itself, as it scares the Nali villagers. A good place to fight is near the area that Tip #7 recommends.
(If you are returning with one or both Keycards...)
Nexus 10: You can put the Keycard into the control panel on the Moon Portal, and if you have the other Keycard, you can use that one also. Reinstalling both Keycards in the Moon Portal will cause it to open, and it will allow you to be transported to the planet's moon.
Nexus 11: If you have both Keycards, then there is nothing left for you to do except go to the moon through the portal. Be sure to stock up on everything you might need or want before entering the portal, because this is the last time you will be in the Nexus.
Sets of Items to buy: (1) A SmartDisk, 2 Nali Seeds, and a Shield Belt; (2) 9 Sticky Bombs and an Invisibility item; (3) a Detonator Pack, a Searchlight, and a Superhealth; (4) a Tri-Shotgun and 15 extra shells; (5) a Chain Gun, 200 extra mini-rockets, and an Assault Vest; (6) 24 Railgun charges, 15 frag shells, a Detonator Pack, 100 Liters of kerosene, 25 Shotgun shells, and 300 mini-rockets.
Buying and Selling Tips:
- You don't have to pick up everything when you buy the contents of a Nali's hut. You can leave something to buy later, but it will cost you another ruby to get it again, unless you finally pick it up before you leave the Nexus.
- Don't be too worried about hoarding Nali Rubies. Whenever you leave the Nexus, you will always have a chance to pick up one more ruby before you make it back to the Nexus. Usually, the only reason not to spend the rubies on something is that there's really nothing that you need.
Other Significant Inventory Items: Asbestos Suit, Shield Belt, Superhealth, Searchlight