Robert Patrick did not receive an Oscar nomination for portraying the T-1000 in Terminator 2: Judgment Day.
The difference this time around is the machine is this time sent to kill the boy John Connor (Edward Furlong) rather than his mother Sarah (Linda Hamilton), and that the original type of terminator the T-800 (Arnold Schwarzenegger) has been sent back also to protect the boy. In this we have the advancement of the villain, but also the advance of the performance of the murderous android. An early instance of that being Yul Brynner in Westworld which was a heavy influence on Arnold Schwarzenegger's performance in the first film. In both of those instances they were playing personifications of bulky brute force who were more intended to intimidate rather than blend in. Notably the performances of both mostly stressed though the idea that these were machines acting the role of a human not a mix of the two, again other than a few minor hints to the contrary. Robert Patrick is allowed to continue this tradition, though in a very different way as the T-1000. What is continued in the tradition is that idea of the machine being the overarching characteristic, which Patrick also uses in his performance, but the thin Patrick, a far cry from the bulky Schwarzenegger, requires a rather different approach to create a menace within the machine.
Now one form of this is the ability of the T-1000 blend in not only in terms of taking the form of some of his victims as a disguise but also to pretend to be a normal human being. This is shown initially within the film when we are first introduced to the character, which I believe was even an intended twist ruined by marketing, that there are no early indications that the T-1000 is a machine as we see him operate looking for John Connor as a police officer. Patrick is terrific in terms of realizing this sort off strange style of T-1000 as he assumes human interaction which portrays as good enough, but not quite. In that he shows that while you'd probably accept the T-1000 as human in a quick conversation things would seem a little off once you spend a bit more time with him. Patrick though does some careful here within his physical performance, which is a major facet of his work here, which a lack of aggression. He moves and speaks with almost too much ease and calm to the point it is unnerving knowing he is an evil machine, though it wouldn't immediately raise any flags for a normal human. Patrick efficiently creates a disturbing illusion as it isn't quite right, a machine assumption of what a human want to see rather than the genuine article. The highlight of this side being his horribly off-putting yet soft delivery of "Say, that's a nice Bike" to a police officer he's likely going to rob and murder.
Nearly the rest of his performance though is defined even more fully about this machine with the one purpose to kill his target with no regard for anyone or anything in its way. Patrick's physical performance brilliantly embodies this idea in every aspect. He creates an artificiality, however notable as this unique artificiality against say the more bulky machine movement previously seen in Schwarzenegger, and Brynner's performances. Patrick develops this idiosyncratic style within the entirety of his physical work that rather fascinating. He moves not efficiently though as human would move, but in his own way. This right within his running in particular that Patrick makes it seem appropriately swift yet wholly unnatural within how precise his movements are, but also how they are not of a typical runner either. This of course amplified by his complete lack of fatigue, but the very motions help to create the menace of the run that is unnerving. My favorite aspect of this though is probably the consistent face that Patrick bears. Patrick fashion a terrifying grimace that feels that of a bird of prey, and again is perfectly inhumane. He makes it this horrible creation of a machine fashioning this expression to put terror in his targets, and how he keeps it with only this singular emotion of a distant hate makes both his work remarkable but also likely contributed towards the iconic nature of the character. Of course this is not a great deal of variation beyond that, but nor should there be as Patrick is playing a machine with a singular purpose. There is perhaps one moment that suggests otherwise at the very end of his performance where has been repeatedly shot by Sarah Conner and nearly killed until she runs out of bullets. This leaves his one action one could argue has some sentience as he does not simply go to kill again but first wags his finger seemingly to indicate his dislike of what she did. An outlier, though perhaps Patrick's greatest moment. It not only is creepy as Patrick maintains his unique expression, but even the finger wag is actually a great bit of acting by him strangely enough. He doesn't wag it only using the finger as human would, but rather more machinesque using the entirety off his hand to give the menacing gesture. I'll admit that's a lot on a single moment but I adore that moment. This performance, despite being in a bit less of the film than I remembered, I find it more impressive the more I think about it. Patrick completely reinvents this type of villain into a brand new original form, that uses ideas of his predecessors however in a brand new and wholly distinct villain.