Having just gave up on Epsilon Mission 3: Scrapyard, I just want to say that whoever designed that mission is a rat bastard. Trying to capture those Oil Derricks early on with only 3 Epsilon Adepts is excruciatingly painful to accomplish, and the loss of one Adept significantly hampers progress. All those damn Allied infantry crawling around the oil field are hard to dislodge, and mind-controlling those Engineers needed for capturing the Derricks is agonizing, as there's only so many engineers there, and they can't be replaced if one dies.
Once I've managed to collect $10,000 and finished the first objective, the rest of the mission should've been easier - Rashidi's outpost is now mine, and I can use the stolen Stalin's Fist to produce Mantis Tanks. However, one little thing ended my playthrough of that mission soon after: Rashidi's Stinger was apparently a critical unit, and it got killed when the Americans attacked the outpost, resulting in a "Mission Failed". Now, there was a warning given that said that Rashidi and the Stinger were important somehow, but such a small thing slipped by my attention. I tried putting Rashidi in the Stinger to see if that gave me a repair unit, but no dice, so I didn't bother with it further. Until it died, that is.
And this is on Easy.
A few things I think would improve this mission a little here:
1: At least give one sniper to you along with the Adepts and Borillo at the start of the mission, so that you can deal with the Allied infantry at the Derricks a bit easier. Also, give the Adepts a Heroic ranking or something, to increase their survivability a little more. If you want to retain the current difficulty level, then make it so that this version is Easy mode, with current set-up being Mental mode; Normal mode would be inbetween - no sniper, and Adepts are Veteran instead of Heroic.
2: Make it a mission objective that Rashidi and his Stinger are mission-critical units that cannot be killed. At least this way one has some sort of concrete forewarning so you won't lose them thanks to a not-so-clear warning that can be easily missed.
Everything else is fine as far as I know, since I didn't even complete the mission yet.