I was watching a pitch for a tactical board game full of mecha, and a standard thought occurred to me: why the fighting? Giant machines are more suitable for industrial work, rescue, construction. For fighting, all you really need is an orbital cannon or a drone with a long-range missile. The fantasy of long, manly punching bouts is stupid.
So I originally wrote up a piece about a noncombat mech game (where you are a catastrophe response team), but there was so much analysis of the fundamental play of the Extended Manly Punching genre of games that it seemed wise to put it in its own post.
First off, we're going to dismiss the excessive variety of unit types. While some variety is necessary, the massive amount of variety found in things like Battletech and Warhammer is more about color, noncombat play, and longevity. And we're just discussing the core play right now. So some variety, yes. Massive variety? Outside our scope.
The "skeleton" of the gameplay is about the interplay of two basic concepts: range and cover. Every combatant has a weapons range and a movement range, which gives them a "kill zone" - they can attack an enemy within that zone on their next turn. Obviously, faster mechs and longer-ranged weapons have an advantage. However, the interplay is confused by cover.
While "range" is largely an abstract mathematical concept, cover is not. Cover is securely grounded in the map the game is played on, and ties the rather nebulous concept of range to a concrete set of constraints. Cover is directional, reducing an enemy's ability to attack you on their turn and usually reducing your ability to attack them. This is a powerful tool against mecha with long range, and is most easily exploited by mecha with fast movement. However, its ability to apply differently in different directions is what makes emergent play.
A team of mecha has a complex team kill zone and cover... cover represented by their overlapping personal kill zones and cover-taking. Flanking damage is also often popular to push this nexus of kill zones apart into a wide-reaching web. By using cover, individuals and teams can selectively protect themselves from certain avenues of attack while opening fire on others. The map may also have built-in terrain features that change range/speed/cover calculations, such as roads that give wheeled vehicles a speed boost, or hills that give mecha a weapon range boost.
This is the heart of the game. The web of kill zones you use, and predicting how your enemy's web will evolve. There's enough known information (current deployment, ideal ranges, movement speeds, and terrain) to predict several turns in advance, but there's enough variables (and sometimes hidden information) that predicting is difficult and risky. So you get a very engrossing system where it's always a challenge to read ahead. Unlike simple "rock paper scissors" fights, this emerging web of kill zones is deeply tied to the terrain of the map, and therefore it is not simply a matter of predicting what your enemy will do... but where and when they will do it.
Basically, the whole system relies on
1) A pair of basic numeric constrains which are largely interchangeable but can be combined and have unique applicability (weapon range and speed)
2) Something that deeply ties those constraints to a complex, unique environment (cover)
3) Multiplying that together several times (teams of mecha)
4) Adding meat with secondary constraints such as armor and ammo, and creating variations to mix it all up
That is my analysis, at least.