The game was okay, I liked it enough. The story was all conspiracy theory and Deus-Ex like. Even had a Hong Kong throwback. That said, the game had some serious mechanical problems IMO. I just got bored and couldn't finish it.
My main, huge gripe with the game is stealth & subterfuge are obviously the preferred way to play. Stealth (non lethal takedowns) rewards the player with more XP than just shooting them. The smooth operator bonus for not triggering alarms is pretty big as well as the Ghost bonus for never being seen.
In Human Revolution there were also really weird things you got XP for too. For example, I vividly remember at one point in the first hub world thing after your first mission, there is a fence with a locked door and you had to get to the building behind it. You didn't get XP for getting in the building, you got XP for getting around the fence.
This lead me, as a somewhat OCD, minmaxing, completionist to hunt for stupid XP bonuses everywhere. That fence in particular granted you XP for hacking the door open, and for stacking up boxes to just jump over it. And I do mean and. I literally unlocked the door, got XP. Went back out, stacked up some boxes and jumped over a fence with a wide open fucking door and got more XP. It was asinine and stupid and there were more than one instances of that, I just can't recall.
The original Deus Ex played a magnificent balancing act in that pretty much all play styles were rewarded equally. Further, you didn't get XP for killing a guy, or shooting them in the head, or using a "takedown" move or whatever. You didn't get XP from hacking random things, etc. You got XP for completing objectives or finding hidden areas.
In the first Deus Ex, you didn't have to be. Your playstyle was equally as valid if you wanted to use explosives to blow up most doors, or find passcodes on guards, etc. In Human Revolution, not only do you gain literally double XP for non lethal takedowns, you gain XP for successful hacks, and there's a lot of them.
This leads to completely fucking stupid instances where I'll have the passcode for a terminal, but elect to hack it anyways because a level 5 device gives you 125 XP. There is literally no reason Adam Jensen would do this, but it's more beneficial to do it.
Finally, the HR boss fights. Everyone complained about them, and they were just friggin' weird and out of place. For a game that so heavy handedly forces you down the stealth route to then pretend it's an action game is just mind bogglingly weird.