The expansion pack to Tiberian Sun is more akin to an entire game in itself. The pack gives us two new campaigns, complete with FMV cut scenes and new units.The story follows after the defeat of NOD and the apparent death of Kane, Nod's Artificial Intelligence unit CABAL attempts to take over the world. Eventually GDI and NOD reluctantly have to join forces to prevent CABAL from conquering the world and turning everyone into cyborg monstrosities.
New units for GDI include tanks that use directional microwave energy beams, as well as Titan artillery, that while inaccurate are able to lob three shells with a fast rate of fire over more than a screen's distance away. GDI also gets drop pod troops (akin to paratroopers in RA2,) an electromagnetic pulse cannon that can disable armor in order to stop tank rushes, and the "Firestorm defense," which is an impenetrable energy shield that can stop Nod missile attacks and instantly destroys any unit flying thorough the barrier or on top of the barrier when it's activated. Nod gets Cyborg Reavers, which are spider like and can shoot a web to immobilize infantry, a new Tiberium waste building and harvester that can collect tiberium vines in order to make tiberium gas warhead bombs, as well as the "Fist of Nod," which is a mobile war factory, able to create vehicles on the battlefield.
The new units add a lot to the game and encourage separate types of strategy for both sides. The combination of Titan artillery, mobile radar stations, EMP cannons, and Firestorm defense can make a GDI base practically invulnerable to everything except a large, massive strike. The drawback of the firestorm defense is that anything on the rail-lines is instantly destroyed when it's activated, even your own units (harvesters have the habit of hugging the walls when going to and fro, and thus end up in the wrong place at the wrong time a lot.) Also it only lasts for about 30 seconds, so the best usage is to surround key structures like the Conyard, refinery, radar tower, etc. For Nod, the Fist of Nod makes it easy to quickly build a large force in order to overwhelm these defenses.
The new missions are pretty decent, and most of them have some kind of objective to complete before you get to kill everything on the other side. The GDI and NOD campaigns are supposed to be taking place at the same time, and there are story elements that you need to play both halves to fully understand (such as the assassination of the Mutant leader Ummagon.) Some of them are somewhat non-traditional, such as one where GDI must quell a riot without actually killing anyone (harder than it seems.) Final mission of both campaigns is the same, where both GDI and NOD attack CABAL's central spire at the same time, and Cabal reveals himself to be a gigantic robot that proceeds to pick apart your entire army, truly awesome.
Yet another solid entry into the C&C universe. This expansion pack is somewhat hard to find on it's own nowadays however it was included in the C&C: The First Decade budleware released in 2006.
Graphics: The FMV is somewhat grainy and the juxtaposition of human actors with GCI backgrounds and vehicles can get laughable in certain areas. In-game graphics use the same engine as the core game, so no complaints there.
Sound: I seem to have trouble getting the sound to come out right under Windows XP, the EVA voice is very faint while other sound effects are glaringly loud (such as the harvester making a deposit, which nearly drowns out everything else.) However I didn't have this problem on my old Win 2000 machine so perhaps it's just my particular setup.
Gameplay: The new units and buildings do a lot to balance up the sides, and encourage GDI to turtle up while Nod goes on the offensive. The unique missions in the campaigns do a lot to keep the game fresh while CABAL is quite possibly the most evil video game boss ever.