It's literally Deus Ex with fewer letters
Architecturally and thematically, Dex is a 2D side-scrolling interpretation of Deus Ex: an open-world cyberpunk dystopia that encourages varied playstyles. It's an ambitious design to ape, and while Dex pulls off a surprisingly-good narrative, the execution of its gameplay leaves much to be desired.
Dex's story starts with a cryptic message from an elite hacker, a "chase" sequence (low-key since it's also a tutorial), and the reveal of the game's central conspiracy: a shadowy techno-oligarchy attempting to control society with weaponized AI. ... that summary may sound a bit hackneyed, but the game's writing and characterization are on-point, full of sordidly detailed technobabble to flesh the story out.
The pacing of story missions is a bit wonky, in part because a lot of exposition is saved for the end, but especially because some earlier missions feel like wild goose chases. To progress the story you need a hacking upgrade; but first you need to get an augmentation from the doctor; but first the doctor needs some equipment from the store; but first the equipment supplier needs you to run an errand; these missions are pretty transparent in their purpose of introducing new characters by stringing you along.
On the flip side, Dex's optional side-missions are more compartmentalized, and really great at making the game world feel alive. These missions are full of well-polished details like emails that reveal characters' secrets, notes that hint at safe combinations... the same kind of satisfying minutiae that makes Deus Ex so engrossing.
Sadly, inbetween talking to characters and hunting for information, the rest of Dex's gameplay is kinda just bad.
Melee combat is a mess, as enemies love to block your blows and knock you down (interrupting the game's flow while you wait for Dex to stand back up). They also take and deal out plenty of damage; I seriously could not get through the game's introduction until I lowered the difficulty. Gunplay is also a mess, as bullets don't do enough damage to stop enemies from getting in your face -- also, the control for aiming is the same as the control for dodge-rolling, so be careful with that!
The hacking interface is basically a twin-stick shooter, and on top of being fairly repetitive, it relies on an energy resource which you have to exit the interface to recharge. Lengthier hacking sequences are an exercise in entering the hack, making incremental progress, going back to the exit, recharging, and repeating several times over.
All of these mechanics can be made less awful by investing skill/upgrade points against them: punch enemies harder, shoot at them more accurately, hack faster, et cetera. But even fully-upgraded, these core components of Dex's gameplay peak at "mildly annoying." At their worst - especially early in the game, when you don't have upgrades yet - combat and hacking are frustrating chores.
And while Dex embraces the spirit of Deus Ex in providing non-combat methods to solve problems, in practice it's got the same flaw as Human Revolution's bosses: there are some fights that you just can't sneak or hack your way around.
Dex is impressively competent at the storytelling aspects of a techno-conspiracy thriller, and its world-building sidequests are genuinely awesome. But the game's non-narrative mechanics are poorly executed and un-fun, ultimately bringing the whole experience down with them.
Better than: Deus Ex: The Fall
Not as good as: Deus Ex: Human Revolution - The Missing Link
This game was "enhanced" at some point in the past few years: which makes me wonder, and fear, how rough its original gameplay might have been.
Progress: Finished on "Casual" combat difficulty.