GMDX is an award-winning large-scale modification for the 2000 PC classic Deus Ex. GMDX addresses the many flaws of the game, polishes it to a very high standard, and adds new layers of depth that one would have hoped to see in a sequel. GMDX is executed with the strict parameter of staying true to the original design principles that define Deus Ex, and seeks to improve all aspects of design excluding the plot and soundtrack. The cumulative result thus far is said to be, and aims to be the "definitive Deus Ex experience".

Marvin42 says

10/10 - Agree (26) Disagree (1)

If you followed the development of GMDX for the last few years, you know the drill: New version, new enhancements, GFX updates, and bugfixes - same old, same old? Of course not. v9 of GMDX is the logical conclusion to v8's approach towards a major redesign of the combat & AI, stealth, and RPG systems.

What do I mean by that? Take combat, for instance. The original Deus Ex was never a stellar example of an ego shooter who could compete with the classics of the genre at the time. There were a lot of different systems in place to empower the player to try a large variety of playstyles but at the end of the day, the rather dumb AI, the terribly imbalanced weaponry and the problems associated with that (skill and augment choice, inventory concerns) never really encouraged anyone to move out of their comfort zone (AI abuse, upgrading the rifle skill).
Starting with v8 and realized to its fullest extent in the new v9, the combat has been polished to a level where Deus Ex can confidently hold its own as a competent shooter thanks to vast improvements w.r.t. enemy AI in particular. Enemies are constantly on the move, know when to take cover and wait for an ambush, can even throw down suppressive fire and know much better when to flush you out with a grenade or enter a melee fight if the player is getting too close. The robots learned a lot of new tricks (don't get one close to death if you're standing next to them!) and new enemy types added to the late game really ramp up the difficulty where the original became laughably easy. A lot of this was already put in the last version, but v9 simply fleshes everything out even better. Guns are improved and more customizable (just take a look at the assault rifle), Snipers have less superhman reflexes, enemies are much more unpredictable, especially during stealth segments.
Going along with these changes are improvements to overall balance, with special attention given to the augmentations which have been adjusted in several places and are even seeing some new additions to make things more interesting. Dozens of little tweaks to interface, audio design, or player movement as well as a bunch of (vanilla) bugfixes complete the picture.

Another big focus of this newest mod iteration are the graphics. GMDX veterans will already be familiar with most of the extensive level design changes, now there's even more of them, with better looking textures and a few custom models sprinkled on top. DX is looking better than ever, without any of the mediocrity found in other mods such as Revision. I won't go into detail here, as the website does a good job of showing a few examples of these touch-ups.

All in all, people familiar with GMDX will probably already have played v9 to death - if you didn't so far, stop hesitating, cause if you liked the previous releases, you'll also love this one.
If you're new - strap in, you're going on a ride. The biggest strength of Deus Ex was that it was much more than the sum of its parts. Now that all those individual parts have been brushed up to such a high level, the whole game is much better for it.