Within the context of its contemporaries and age, it holds up relatively well, but if you hold no memories of this title - not so much. I got too frustrated to continue after the first handful of levels due to instant death mechanics just outside the camera's range and questionable hit boxes for the combat. I just can't afford the time to memorize sections of levels; and even if I did I'm not sure if my modern sensibilities would allow such a thing anymore. A lot of the difficulty comes from purposefully annoyingly designed sections of gameplay. Games like Super Meat Boy have truly surpassed and rendered Gex obsolete, so unless you are curious about the history or haved played it as a child there is little reason to return here.
Basically, GTA and Max Payne had a baby and its name is Total Overdose. Mechanically nowhere near as good as either, but there is so much charm here that it doesn't really matter. Total Overdose is just a truly fun time. After last playing this in like 2005 on the PS2, I was surprised at how well the game aged. Somewhat substandard mouse aiming aside, it still plays wonderfully. The characters, settings, dialogue and action are all just as ridiculous as I remember.