Dex is a strange mix of 2D platformer - rolling shooter - proper RPG and, for me, story teller. The plot is pretty standard for a cyberpunk game. Default Evil Corp ltd. vs. Hackers of the People. Evil Guys have a Cunning Plan and this is where the heroine comes in. Dex can connect to augmented reality wireless. As you've probably guessed, hacking and AR will be integral for the story.
Hacking stuff is really fun in this game. Unlike some other titles, Dex's devs didn't try to mimic real world (which usually ends badly) and instead gave us completely separated "minigame" mechanic: Dex's AR alter ego is free to roam in the AR world, dodging programs-enemies and shooting them. You'll encounter black holes (creating gravity), firewalls (ouch) and plain old traps. Kind of a tower-defense, from the point of the attacker. Neat!
The English voiceover is fine and Czech subtitles are translated using Czech names, jokes and events - having little skills in other languages I can only hope other they received the same amount of care, because it'd be shame to suffer from word-to-word translations.
The only major downside I see in Dex is the game lacks some kind of "middle" difficulty, since the "hard" one can be - at least in the very beginning - really unforgiving.
It really depends which augmentations you buy at what stage of the game, but luckily you'll get somewhat guided by the quests and the rest can be fixed with in-game credits, not by having to load an earlier save. That being said, _do_ save often, since some of the death traps are not really obvious.
It took me 15-20 hours to complete my playthrough, and I'm on the explorative edge of playstyle. The story is pretty much linear with the edge choices (help person A or B) having trivial impact on the main story. The fights and hacking are fun enough to drive me through the game, but not enough for me to replay within a year. But within two? Likely.