Set in the year SE 3256, the player is thrust into mankind's first interplanetary war between the Earth Alliance and the Ares Confederation. As the promising captain of the experimental dreadnought prototype, codenamed Sierra. Your sole objective is to help turn the tides of the war, utilizing the ship's advanced combat systems, flexible energy allocation and optimized platform deployment capabilities. To the captain, the core principles of prudence, guile, resource management and patience are essential to survival. The technology incorporated in Sierra allows it to explore multiple paths to victory: evade and assault enemy ships in classic broadside warfare; research armaments and upgrades to outgun the enemy fleet; or outnumber them with remotely-controlled weapon platforms. Rout the enemy’s armada in order to quell the rebellion and save Earth from the corrupt colonials.
In a lot of ways this game is more like an action RPG than a strategy game: you have various stats that can be upgraded, can can around equipment, and maneuver your ship for maximum firepower (you only command your personal battleship). None of this is a bad mind you, just be aware of it in case you mistakenly thought that this was a strategy game.
And honestly, it's really a lot of fun commanding your ship. There are lots of little details to keep in mind; where your turrets fire, managing the energy in your subsystems, keeping your shield from being completely destroyed, determining when and where to deploy platforms, etc. At first it seems like a lot of little detail to start the player off with, but the game is paced well enough that you don't have to master all the controls until a third of the way through.
On the downside not managing your resources carefully, or upgrading something you don't need early on, can really cripple you for some missions. On the brightside, even if you lose a mission you still get a few resources, so if you've backed yourself into a corner you can at least dig yourself out eventually.
Later missions tend to devolve into a war of attrition, where you basically fire everything you've got at its maximum range until enough gotten through the enemy's point defense screens to do damage, which might not appeal to some people.
Visually, it's really quite enjoyable. You can watch each of your turrets track targets and fire individually - same for the enemies, and watching space light up with explosions as missles and fighters are bounced by your point defense is always entertaining.
The plot is mostly there to move you from one fight to the next, but is never obnoxious or overbearing.
So, the TL;DR of it is that if you like tactical action RPGs, or sci-fi space battles in general, then you'll definitely find this medium length game entertaining. If you were hoping for a slow strategy game, you may want to look elsewhere.
Operation SD just isn't much fun. Many fights devolve into endless wars of attrition where you hope that maybe someday your attacks will manage to pass through the enemy point defense screen and deal damage. While there are certainly glimpses of strategy like enemies that only have point defenses on one side they all fall apart when the enemies simply clump up (with enemies with PD on one side and those with it on the other bunching up to form 100% coverage) and all you can do is sit outside that clump and try to unclump it so the enemies won't shield each other with point defenses anymore.