Most people will compare Deus Ex: Invisible War to the prequel, Deus Ex. This is a natural comparison, as the first game was not only hailed as one of the finest of its genre at the time, but arguably still one of the best FPS's around, despite its aged graphics engine. I will compare the features of DE:IW to those of the prequel, but I will base my judgment of the game solely on its own merits. For simplicity, I have divided the review between the two parts: The first half of the review is the standalone review, the other half is the comparison to Deus Ex.
Standalone Review
As a game all its own, DE:IW is not as bad as some would have you believe. The graphics engine, a modified version of the Unreal II engine, renders the characters and settings quite well, and I did not experience any graphics anomalies. The physics engine, a slightly altered version of Half-Life 2's Havok engine, describes the physics of all in-game objects fairly well. The ragdoll physics displayed by dead NPC's is realistic and believable, as are the player's interactions with inanimate objects.
While some may complain that the plot takes too many convoluted twists, I found it intriguing and on par with the first game. The most interesting aspect of the game revolves around the moral choices with which the player is faced. Unlike the first game, the choices that the player must make come across as morally ambiguous, forcing the player to truly consider the choice and its implications. Unlike the first Deus Ex, I never felt confronted with a choice that had an obviously good or evil choice. The script in DE:IW does an excellent job of keeping the plot totally neutral in relation to the different factions with which the player can align himself, forcing the player to make a deliberate and conscious moral decision, as opposed to choosing between the side that is obviously good and the side that is obviously evil.
The player enhances the character through nano-technology. The player will pick up so-called bio-mod canisters throughout the game, each one giving the player a new ability. Sadly, this feature of the game falls flat. The player will find that only a few of the bio-mods provide any useful enhancements. In fact, the player will probably complete the game only having used two or three different bio-mods throughout. This feature disappointed me greatly, as it stifled the player's desire to really make his character unique.
The interface is fairly clunky and unintuitive. This is probably my biggest complaint regarding DE:IW. The player can only carry so many items, and assigning these items to different slots in the player's inventory proves fairly easy. However, once the player decides that he wants to switch an item out for another item, it becomes a fairly complex sequence of highlighting one item, clicking it, then highlighting the other item, clicking it, then hitting the correct button to make the switch. This is highly frustrating, especially at the beginning of the game, as this is totally different than pretty much every other FPS (or any game with an inventory system, for that matter).
The ammo system utilizes a universal-ammo system, meaning all weapons in the game draw from one type of ammo, just at different rates in relation to the type of weapon (semiautomatic, fully-automatic, or steady-stream, such as a flame-thrower). While this system is wildly inaccurate and one heavily derided by many critics, I found it nice not to have to search everywhere for one specific type of ammo. I also enjoyed the fact that I was not unable to use a particular weapon in a particular situation, so long as I had the universal ammo, as opposed to some games in which the player is forced to take another course of action simply because he doesn't have the right type of ammo for the weapon that he would like to use.
In all, these negatives are only minimal detractions. The game still satisfies on a level that few games achieve, especially on the level that I really think the designer were trying to hit: Forcing the player to make judgment calls that were neither right nor wrong. The game succeeds on this and several other levels, including graphics, sound, and physics. The storyline and unique moral choices will cause most players to overlook the primarily useless bio-mods.
As Compared to Deus Ex
As compared to the first game, it becomes obvious that DE:IW was designed more for the consoles than for the PC. The levels do not sprawl across wide areas, allowing the player several different paths to the objective. The universal-ammo system promotes a more haphazard approach to some objectives, as the player will have ammo for all types of weapons, whereas weapon-specific ammo as used in the first game forces the player to strategize a little more. However, the two glaring differences center around the bio-mod system and the choices that confront the player.
Firstly, the original Deus Ex had not only a bio-mod system, but also an RPG-like skill system that was totally separate from the bio-mod system. This encouraged the player to create a totally unique character who could be good at a range of things or great at just one or two. This skill system was totally dropped from DE:IW, and this, I think, represents to the most thoughtless exclusion. As stated, the game was definitely "dumbed down" for console players, but the exclusion of the skill system really detracts from the game.
Instead of the skill system, DE:IW rolls the skill system in with the bio-mods. In the original game, the player used to the skill system to upgrade the character's weapons-handling and field abilities. In DE:IW, these features are upgraded through bio-mods. This greatly over-simplifies the entire ordeal and makes for a fairly bland playing experience.
The original Deus Ex employed a forking plot just as DE:IW does. However, the choices in the first game become very obviously choices between right and wrong, especially towards the middle and end of the game. In fact, around the 1/3 completion mark, the player is forced to sever ties with the organization for which he works and join another faction. This does not appear in DE:IW. As stated, all choices in DE:IW are faction-neutral. Any moral obligation that the player feels is internal and does not stem from the designers throwing a positive or negative cast on one faction or another. The choices in DE:IW are superior to those of the first game, as in the first game, it became obvious which faction was in the right and which were in the wrong.
Even though DE:IW eschews some of the features that made the first game great, I can still easily recommend it for those who have completed the first game. The graphics, sound, and physics easily outshine that of the first. While the absence of the skill system and the dumbing-down of the bio-mod system disappoint, the tightly-written and faction-neutral script will keep the player hooked just to see how the game ends.