Now it is true that I loved all of Nicholson's nominated work in the seventies all four of those performances are oustanding. It is also true that some of those performances particularly One Flew Over the Cuckoos Nest and Chinatown are completely filled with Nicholson's unique style. The only thing was in the seventies Nicholson used his unique styles always within in characterizations creating remarkable portraits of the men he portrayed. Later on Nicholson started doing his mannerism as a separation thing that he just has to do, and he stopped using them as effectively because of this reason. In fact this is a problem I have with many of his later performance, particularly his work in The Departed because that was just one long over the top Nicholson mannerism fest.
Finally to get to the point is that his use of his mannerisms always seem to be Nicholson performing them rather than actually being part of the character in this performance. This is especially true early in his performance as he almost wants to make an impact in his short scenes by doing his trademark shtick. It just never seems completely true to his character, in fact it is actually a bit distracting. Luckily though Nicholson after his somewhat shaky early scenes does settle down, and actually delves into becoming his character. I don't want to be mistaken though Nicholson is not bad in these scenes, just more of a little too self indulgent and obvious for his own good.
Later on in the film when his character of the womanizing, thrill seeking former astronaut starts a relationship with Aurora Greenway (Shirley MacLaine) Nicholson certainly comes into the role quickly. He certainly is appropriately boisterous and energetic in his role. His character just wants to enjoy life to its fullest, as almost compensate for the fact that he will never have his biggest thrill again which was to go into outer space. Nicholson has a great joy of performance here that works perfectly for his character who only wants to enjoy himself. Nicholson's smile is constantly on display here, and it certainly fits for his sometimes devious character.
Although Nicholson somewhat became typecast as the love interest for a reserved as well as strong willed woman as seen in As Good As It Gets, and Something's Gotta Give his dynamic with Shirley MacLaine certainly does work here, and it shows why Nicholson probably found him self cast in films with rather similar situations. Nicholson always shows the womanizing Garrett early on trying every trick he knows to try to get his way with Aurora, but is rather flabbergasted by the response he gets. Nicholson plays this well finding a great deal of humor in the Garrett's attempts, as well as his reactions to Aurora's sometimes quite stern responses.
Even though their relationship at first is mostly a series of comedic exchanges caused by their personalities a love relationship eventually does develop. This is not a long precise one, but the actors portray it convincingly. Nicholson carefully but effectively shows the deepening of the relationship almost by Garrett letting loose just a bit, and showing Garrett turns off the part of him that wants just instant gratification. It is a subtle transition but very well handled by Nicholson.
Later on in the film though Garrett becomes hesitant to pursue the relationship due the commitment he is feeling toward something the freewheeling astronaut wants to avoid. Nicholson is good in these later scenes showing Garrett a very much confused man who wants to be there for Aurora to some extent yet at the same time does not want to become too involved either. It is certainly a strange combination of emotion, but Nicholson brings to life wonderfully. He shows him as a man who is always contemplating his situation at almost all times, although Nicholson even in the most serious scenes keeps just the right glint of Garrett's more mischievous side.
All things considered this is a good performance from Nicholson. Creating an entertaining presence for the film and an effective foil for MacLaine's Aurora. I will say that I do not put it as a great performance, or as one of Nicholson's very best. It never achieves the greatness of his earlier work, and part of the reason I would say is his overuse of his trademark mannerisms early in the film, when he could have shown as more of Garrett at that point. Instead too many of his early scenes feel like Nicholson just doing his thing rather than a full fledged character. Nevertheless he does find his character as the film progresses that I would still say this is an enjoyable somewhat standard performance by a great actor.