Command and Conquer Red Alert 3 Walkthrough
Santa Monica: Rage of the Black Tortoise
Mission Objectives:
When you first start, build two dojo cores, then two generator cores. Once the generators are online make two refinery cores. During this make two engineers to capture the oil derricks to the east and south. Make ten tankbuster units from each of your dojos to destroy the houses and pick up more cash crates. It seems like a lot, but they'll come in handy later.
When the houses are clear, place a mecha bay core. Make four mecha tengus to defend your base from infantry. While all this is happening, send three of your tankbusters north to the house next to the seaport. Snipe the three power plants from there and bring their power offline. Once your tankbusters are done, send them all north and walk into the base. Kill the peacekeepers but don't destroy the turrets. Destroy the two power plants and prospector (which will try to crush you). Once the power plants are down you'll be free to romp the joint and destroy everything except the construction yard. Work on twelve engineers back at your base during this.
Send a refinery core and a pair of engineers up north. Capture the derrick and construction yard (sell) and place the refinery at the ore mine. This is a nice extra source of income. Back at your base your ten engineers should be getting done. Hotkey the two sudden transports and look to the north for an enemy to disguise them as. Once you have, send them to the south by the oil derrick, and use alt-right click to make them follow a path up the eastern side of the map to the enemy main base.
At your base start building more units to defend and later attack. Mecha tengus are good for anti-infantry and striker-vx are great for plowing through enemy vehicles. Keep a vigil by your base. When your sudden transports make it to the northeastern corner, place one in the middle of the four reactors and deploy the engineers inside. Capture the four power plants and the refinery. Sell all of it. The second transport needs to go closer to their construction yard, where again you'll capture everything then sell it.
Make a total of ten extra mecha tengus and twenty tankbusters. Your next goal is the airbase to the southeast where you have captured a derrick. Take the tengus and the tankbusters to the southeast (on land), kill any infantry then bring your tengus to the sky to eliminate any cryocopters and apollos. Now bring down the rest of the base.
Reinforce them if you must, but you should be clear to destroy the base southwest of the one where you performed your sneak attack. Destroy everything here. Once the rest of the enemies are gone you can focus on capturing the media centers, destroying the amusements and obliterating the observatory cannon. This may take some practice, it's a fairly difficult mission. Once the northeastern base is down it's much easier.