Also, I wouldn't separate takedowns and "real gameplay". I mean, how are we going to come up with a way to make scenarios such as that above takedown without incorporating it into a command or two? How would you design takedowns and QTE-like gameplay sections without resorting to button commands? It would take an astronomically advanced controller, the superhuman ability to use it effectively, and the extreme cost to mass produce such a complex abomination. Games' budgets get higher and the animations get better, but it's very difficult to implement them in a more advanced fashion than simple button presses. It's just pointless to get mad over the feature itself. Rather, get mad over how much it's abused in certain games to the point where it's no more than an interactive movie. HR doesn't fall anywhere close to that, though.
Case in point: Why get mad over something like pressing a button and watching a 2-5 second takedown? Did you not approach a guard from behind in DX1 and press a button which activated the prod, baton, knife or sword attack? Did you not wait a couple seconds for him to drop, loot him, then carry his body? Can you not do this exact same thing in HR? The only difference is the quality of the takedown animation. It's something nice to look at, rather than just watching a guy fall flat on his face for the millionth time.
The difference is that failure was possible when using melee weapons in the first two Deus Ex games. Maybe you aim for the wrong part of the body, maybe the guard moves at the last second and you miss, maybe you're simply not strong enough and a single blow isn't enough to down the enemy. With takedowns, your only limitation is how many charged energy cells are at your disposal---conceptually weird, as Jensen inexplicably can't punch people while his batteries are recharging. I mean, the whole reason the energy system was designed the way it was is because the takedown system is so horribly broken. If you were to allow the player to engage in melee combat at all times with the efficacy of a takedown, the game would be a total joke. And even
with the energy limitation, it rarely prevents you from takedowning every enemy you come across---you're simply forced to sit around for a minute, twiddling your thumbs while your juice refills. And considering that stealth is basically just as easy in Human Revolution as it was in the original, it's not as if there is any real challenge in the approach, either.
No, I'm very comfortable with describing Deus Ex HR's takedowns as non-gameplay. It's the closest thing to an actual win button I've seen in a game. And due to that fact they were forced to further limit the player in other arbitrary ways. This was just about the most significant failing of HR, and why I really have no interest in a second play through.
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On finishers in general:
A game should never lock the player into a finisher once it's been initiated. If the player hits a movement key or action button, control should immediately be returned. There are many times in which a game forces you to wait as an animation runs, meanwhile the enemy AI is unaffected and proceeds to kill your character as they stand there staring into space. I also run into situations where I begin a kill move, but before the attack actually takes place I notice another enemy in the area. If I'm trying to avoid detection, it makes sense to withdraw the attack so I can remove each threat without the other being aware. Instead, the attack goes forward and I'm forced to deal with the consequences of something I did not want to do.
In short, finishers are okay---not great---but control should only be arrested from the player in the most extreme of situations.