Cover, and how a half wall became the grammar of the genre

Here is the thing that is strange about cover. X-COM: UFO Defense (Mythos Games and MicroProse, 1994), the game the whole genre descends from, does not have a cover system. There is no cover bonus, no shield icon, nothing on a tile telling you it will protect you.

What it has instead is a world. A wall blocks a shot because the shot runs into the wall. Darkness hides you because the alien cannot see you. Protection is a physical fact about where you are standing, and the game expects you to work it out.

XCOM: Enemy Unknown (Firaxis Games, 2012) replaced all of that with a rule, and the rule is why every tactics game since looks the way it does. Stand behind a low obstacle and you are in half cover, worth 20 defence. Stand behind a tall one and you are in full cover, worth 40. The chance to hit you is the shooter's aim minus your defence. Step around to your side and both numbers vanish, because flanking cancels cover entirely, and so does standing right next to you.

The important part is not the numbers, it is that the game draws them. Every tile shows a shield, half or full, before you move there, and the shot percentage is on screen before you commit. The player can see the deal.

That legibility is why it spread. Mario and Rabbids Kingdom Battle (Ubisoft Milan and Ubisoft Paris, 2017) uses the same half and full grammar in a crossover platform game, which is about as strong a proof of universality as a design idea gets. Gears Tactics (Splash Damage and The Coalition, 2020) keeps the cover rules and throws out the grid, letting you move freely within an action point budget.

A rule that simple has to lie. A chain-link fence, a parked car, a sandbag and a brick wall are all full cover, and a bullet that should pass straight through one of them does not, because the game resolved the shot as a dice roll against a number rather than as a projectile going somewhere.

It also quietly makes the world less interesting. If cover is a property of a tile, the designer's job becomes placing tiles with the right properties, and after a dozen maps the player stops looking at a street and starts reading a pattern of half and full.

The deeper objection is that it hides the physics the fight is supposedly about. When a shot misses, the game cannot show you why, because there is no why. There was a number, and the number lost.

The alternative is older and keeps coming back. Simulate the shot, let the world stop it, and make cover a consequence rather than a stat.

Silent Storm (Nival Interactive, 2003) is the famous case. Almost every wall can be shot through or blown apart, so a sniper nest is only cover until somebody brings enough explosive, and hiding behind a thin partition is a mistake the game will demonstrate. Jagged Alliance 2 (Sir-Tech Canada, 1999) resolves a line of fire through whatever is actually in it, including your own mercenaries, and lets you spend action points on aiming and on stance rather than on finding a shield icon.

Brigade E5: New Jagged Union (Apeiron, 2005) and 7.62: High Calibre (Apeiron, 2007) go further and model the bullet and where it lands on a body. Phoenix Point (Snapshot Games, 2019) is the most deliberate reaction of all: Julian Gollop, who made the original X-COM, built a game where you aim freely at parts of a target and the shot is blocked by whatever stands in the way. It reads as an argument with the game that was made from his own.

The question is not realism. It is whether the player can tell, before acting, what they are risking, and afterwards, why it went wrong. Abstracted cover answers the first half beautifully and the second half not at all. Simulation answers the second half and makes the first half hard work.

The games that feel fair are the ones that pay the readability cost somewhere. If the odds are a number, show the number. If the odds are physics, show the bullet: where it went, what it hit, what was in the way. A player who can see why a shot failed will accept losing. A player who cannot will conclude the game cheated, and they are not being unreasonable, because they have no way to check.

Into the Breach (Subset Games, 2018) settles the argument by refusing it. There is no cover and no percentage, because there is no randomness: every enemy shows you exactly what it will do next turn, and the whole game is arranging the board so that it does not matter. It is the most readable tactics game ever made, and it got there by deleting the question.

RAD Tactics is a squad tactics game for Windows, real time with pause, set after a collapse, with zombies and with factions fighting over what is left. It is in development, and we are not going to describe anything in it that is not finished.

The standard we hold ourselves to is the one above, and it is not a feature, it is a duty. Whatever the rules turn out to be, a player has to be able to look at a fight that went badly and see the reason in it.