First of all: This is an interesting project I would love to see more of
Below are my comments on the missions and main menu.
The main manu
It's cool you have redesigned the options panel (gives it a professional touch
) but shouldn't it be centered? When I first saw it I thought it was a bug or something, but if I understand the code in "UIDlgAlien.txt" correctly, the panel is deliberately placed in the left side of the screen. It would look better if it was centered - if it's the background that's the problem (the background is quite bright so the panel would almost disappear if it was centered), I can make another background for you.
When you enter the "select mission screen", it's hard to read the text (white text vs. bright background).
Mission 1 - The First?
In the first part of the mission where you see Zelenyuk and a bunch of other scientists and soldiers go to the TAWAR, I miss a little briefing about what is going on. What is the TAWAR? Why are these people sent back in time? These preliminary questions could be answered in the mission briefing (you know the text displayed when the mission loads) or better yet - with a video before the first mission starts.
The environment deserves applause - almost flat land with withered, brown grass with a stone and a tree here and there; a few, not very deep, waterholes now and then and almost no wildlife. That's exactly what I can imagine Siberia looks like: a barren wasteland.
When Zelenyuk arrives at N. N. Krestinsky 3 he takes over the command of the base. Why is that? The base already has a commander (the guy speaking over the radio in the beginning of the mission). It's not necessaryly necessary with an explicit reason - you could just add some extra dialogue where Zelenyuk kinda takes initiative of what to do - you know like "repair the damaged buildings" and "build additional breastworks".
Also when Zelenyuk reaches the base I think Zelenyuk should be curious about what the situation is like on the large scale: How are things going with the siberite? Does the Americans pose a threat? Who is the superior commander of the Russian forces? This could be a part of the conversation when Zelenyuk reaches the base, or you could make a query so the player can decide himself/herself if he/she would like to know about these things.
Mission 2 - Science Time
The main base is called "N. N. Krestinsky Area Main Base" - perhaps it's just me, but it sounds weird with the "Area" thingy in the name. "N. N. Krestinsky Main Base" sounds better
I can see in the code (module "main") that Pyotr T. Koneev and Zelenyuk are supposed to look in the direction if each other when they speak in the beginning of the mission, but turning a human unit takes a small amount of time and function DialogueOn is used directly after function ComTurnUnit, so Koneev and Zelenyuk first look at each other when the dialogue is over.
I miss some kind of reason as to why Zelenyuk is chosen to be the new commander of N. N. Krestinsky 2, but perhaps your intented reason was that he successfully commanded N. N. Krestinsky 3 - then I would still like this to be expressed explicitely. Less relevant is who was the former commander of the base and what happened to him?
One of the scientists in N. N. Krestinsky 2 warns Zelenyuk of going near the siberite mine, but there are no consequences of doing so. I like the uncertainty (it's authentic - the Russians don't know much about siberite), but I miss some consequences or some sort. Perhaps they have to make some measurements near the mine or something before they can start using the siberite for research.
The total number of "crate resources" you need in this mission is about 120 and the mission lasts about 20 minutes - those numbers should be synchronised in some way. As it is now, at least 1000 "crate resources" spawn in this amount of time which is too many in my oppinion.
If some crates appear in the area of the main base, why doesn't the engineer go and pick them up?
It's very good that the lab in the main base starts researching something after some time - it makes the base "alive".
It's my impression that N. N. Krestinsky 2 and N. N. Krestinsky Main Base is relatively deep in the heart of Russian territory so it would be likely if a patrol would pass through the area now and then (following the road going north-south and perhaps stopping in the main base for a while before continuing).
Concerning the third medal I think I have an idea:
When the player has researched siberite power technology, Zelenyuk calls Koneev and tells him about the discovery. Koneev is so impressed and excited that he orders Zelenyuk to send the blueprints and the required siberite to N. N. Krestinsky Main Base so the engineers there can build and test the power plant. The player is the supposed to send an engineer with 10 "siberite resources" to the main base. The siberite must be dropped in a specified area where the engineers of the main base picks it up. The engineers then commence construction of the power plant.
When the player has researched all siberite technologies, he/she can choose to end the mission if the power plant hasn't been constructed in the main base yet. If the mission is ended, the medal is of course not given. The mission ends automatically when all siberite technologies have been researched and the power plant constructed.
As you can see, many of my suggestions are about small details, but for me such details are the heart of the game.