Players take turns at offense and defense, but combat happens in real time. When a turn begins, one city spawns units from dropship pads. These units take the shortest path to the enemy capitol and attack it. Enemy towers attack any units who come near. When all units die, the turn ends, and the other city gets a turn to spawn units. Turns continue until one player wins by destroying the other capitol.
City Conquest provides examples of:
- Achievement System: The game awards achievements for actions like using a level 2 Chiller, bouncing a laser off 10 mirrors, or winning a Hard or Expert scenario. There are 100 achievements, worth a total of 1000 points.
- Airborne Mook: Gunships. These fly over enemy towers, straight to the enemy capitol. On some maps, Gunships can skip half the enemy maze. Many players prefer to win by building and upgrading Gunships, because spamming Gunships is simpler than arranging an army of other units. A defender can kill Gunships by building a wedge of Gun Turrets, Missile Launchers and Lightning Towers under their flight paths.
- Anti-Frustration Features: At the beginning of a battle, the game may require you to build a minimally functional city before it unlocks the other buildings. First, you must build a gold Extractor (so you have income). Second, you must build a Gun Turret (so your capitol isn't defenseless). Third, you must build a Dropship Pad for CosmoKnights (so you don't skip your attack phase).
- Chain Reaction Destruction: When the enemy destroys the capitol, it explodes, and every other building in the city explodes.
- Color-Coded Multiplayer: The blue army and the red army have identical units and buildings.
- Earthquake Machine: Ground Slammers. These shake the ground by hoisting and dropping a large weight. This is an area attack against ground units, but not hovering or flying units. Ground Slammers are cheaper than Grenade Tossers (which also hit hovering units).
- Fragile Speedster: Rollers. Low health, but faster than any other unit. They rush past enemy towers to sooner reach the enemy capitol.
- The Goomba: CosmoKnights. Cheap, weak, slow. Most armies build these first. Four CosmoKnights spawn from each dropship pad, so the best use for them is to crowd out enemy towers, but they easily die to towers that attack groups, so Zerg Rushes with them tend to fail.
- Instant-Win Condition: Destroying the enemy capitol wins the game. This action also blows up the entire city.
- Invisibility Cloak: Commandos carry cloaking devices that hide themselves and nearby units. Then they can sneak through enemy mazes. Most towers ignore invisible units, but Disruptors can uncloak them. When they reach the enemy capitol, they uncloak before they attack.
- Life Meter: All units and buildings have health meters. (Units will only attack the capitol, but other buildings can lose health if they fall out of the city borders.)
- The Medic: Guardians. Each one can heal two other units. Guardians have no attack.
- Player Versus Player: Blue army versus red army.
- You Require More Vespene Gas: There are two resources: gold and purple crystals. Gold builds towers for defense, while crystals build dropship pads for offense.
- Walking Tank: Crusaders. The strongest and most expensive units. Crusaders run on two feet and can survive mazes that kill Tanks and Hover Artillery.
- Zerg Rush: This tactic, to rush many level 1 units, rarely works. It is almost always better to build a few units and upgrade them to level 4. On some defense-only maps, the computer will rush a mass army of level 1 CosmoKnights. A player can kill them all with Ground Slammers, Grenade Tossers, or Lasers.