A set of lore friendly campaigns of varying length (mostly short to medium). Mostly classic RTS gameplay, modded with a nudge toward more realism and slightly more relaxed pace.

Focus on gameplay. Story elements are light. They set the stage and tie missions together, but don't expect intricate plots, text novels or fancy cinematics.
Mostly fair AI that generally build units rather than spawn them, and don't have unlimited reinforcements, i.e. attrition tactics are viable.
The overwhelming majority of missions don't have time limits, allowing you to progress at your own pace (as long as you can stay alive).
Little to no handholding. You get your objectives and will have to figure out how to achieve them on your own. You won't get notified about enemy activity (unless there are story reasons for it). You'll have to scout to know what the enemy is doing and when and where they are attacking.

At the core is a significant overhaul mod that makes small adjustments to almost every aspect of the game in an attempt to make it slightly more realistic and more audio/visually pleasing. Here are a few highlights:

Armor penetration is a thing; it will take a long time for small arms fire to take down a tank.
Small units are difficult to hit. Ranged units may miss them completely, hitting the ground instead and kicking up dirt. This means e.g. infantry won't take tank AP rounds to the chest and carry on as if nothing happened, without making tanks extremely overpowered (many tank shots will miss, but when they do hit it will cause massive damage). Note that this mostly affects armor-piercing weapons with no splash damage. A siege tank artillery shell doesn't really care if it misses it's target slightly.
Adjusted unit sizes, nudging them toward more realistic sizes (just a nudge though, nothing spectacular).
Overhauled combat effects. Muzzle flashes, projectiles, impacts, sounds, explosions etc.
Slightly more "weight" to large units. A tank won't turn on a dime.
All units have slightly more hitpoints, making battles take slightly longer and giving more time to micro manage.
Many micro abilities have been toned down. Army composition and positioning is more important than ability micro management.

Currently contains 3 campaigns with a total of 17 missions:

Rogues (Protoss) - 5 missions
Stonehammer (Terran) - 7 missions
Arrival (Zerg) - 5 missions

Credits

Custom models and textures from:

GhostNova91
GnaReffotsirk
Hammer107
SC2PVE
WingedArchon
Cerberus
Zerakim
Glow

Koprulu Chronicles