Twice now, I’ve encountered indoor levels: enemy complexes with patrolling guards, where your goal is not to slaughter everyone, but to reach a certain room or rooms. (In both cases that I’ve seen so far, it also involves keeping a brace of defenseless Engineers alive to reach those rooms, that they may ply their skills.) This is a familiar variation on the RTS, and would have been familiar to players at the time as well: I don’t remember if the original Command & Conquer had levels like this, but Warcraft certainly did.
The game engine doesn’t really know it’s indoors. Apart from a paint job on the terrain, everything looks and acts the way it usually does. You obviously don’t have tanks and airplanes in the corridors, but that’s because the level designer chose not to make them available, not because they won’t fit. One of the basic Soviet defenses is a kind of automated flame thrower on a pole: these are seen spewing destruction at the entrance to most Soviet bases, preventing you from simply storming the place with foot soldiers. They’re present in the indoors scenes too, where they somehow seem smaller, more like a Dungeons & Dragons trap than something to hold back an army. But in fact there’s no change in their range or destructive power — it’s just that the scale of the world around them has been altered.
The real way these levels differ from normal ones is that there’s no base-building. You arrive at the complex with a certain number of soldiers, and you have to keep enough of those soldiers alive to accomplish your mission. This extremely contrary to the way I normally play these games, which is heavily based around accepting losses as long as the enemy suffers losses too, and as long as I can recover from them faster. Here, there’s no recovery. Both of the indoor levels I’ve seen give you a medic, who provides slow but unlimited healing during quiet moments. But there’s no healing the dead. Putting this constraint on makes it feel a bit like a special exercise, like blindfold chess or fistfighting with one hand tied behind your back. It’s easy to become complacent about the abundance of resources in other levels — Ore is not inexhaustible, and indeed I routinely exhaust stretches of it through my profligacy. But the indoor levels teach me to be frugal with lives. If it were to teach me this successfully, it would probably make me a better player, raise my customarily abysmal Economy rating at the end of each map, and make the tougher levels a lot easier.
But I doubt that’ll happen. I’m almost at the end of the Allied campaign already; it’s basically just a sprint to the finish now. And if they expect me to carefully look after the well-being of my people when I switch the other campaign, well, then they clearly need to read up a little on Joseph Stalin.