The Cold War: Toughest: Soviets: 14) Panama Canal

This scenario of the Panama canal is the same as the American version in their campaign.
Basically, ally with one of them and destroy the rest. The first hurdle is the most difficult as you are at war with all of them and need to save metal to make an alliance.
With one mountain, a smelter is necessary and if you don't move quickly, you'll also run out of land to build a second city. A bunker, a few infantry and some copters should be enough to hold out while you accumulate the necessary metal. Although a few subs and cruisers will help with any sneak invasions by sea.
Level 2 commerce should be upgraded early to be able to trade at the market and you'll kinda be stuck not doing much for a while. Aim to fish for any whales and any spare land you can build a city on should be built.
Once you got the metal needed (bout 1k-1.2k), choose an ally. I think Magenta has best bonus this time around as Green just gave me the Tikal temple which didn't help me out all that much last time.
Seeing as your tanks can now regenerate, obviously you'll need to build a lot of tanks. Your ally will help you attack if they can get the space they need so defend them from their closest enemy and eliminate them.
Eventually, the remaining Tribes of Panama will group together as one unit, which doesn't change the battle much at all. Air units should support the ground troops in any way possible while a strong navy will dominate the cities along the coastline so that's where your focus should be first.
Capture the Panama capital(s) to win this scenario.