Very entertaining, but unfortunately has some flaws

Rating: 8/10 (5 May 2018)

Starting with the positives, I thought the film was an overall blast. I was engaged and entertained throughout, and never was I losing my attention. I felt there was clear motivation for the villain, who (unlike most MCU villains), had some personality behind him. The acting and filmography were great, however it's the narrative that for me, restricted this movie to an 8, rather than a 10.
For me, no film should be worthy of a 10, if it includes a disposable CGI army. The first avengers had the Chitauri, the second Ultron bots, and this one, some mad 4-armed aliens. They had no backstory or motive, and only provided action sequences. There was no emotional connection, and I was disappointed that Marvel has allowed this to happen in every single Avengers film to date.
Furthermore, this film is unable to stand on its own. Having seen most MCU films, I knew who each of the pre-established characters was, their motives, personalities, etc. However, trying to learn who everyone was from the film alone leaves a lot to be desired. I know people will argue that more or less nobody is going to see solely Infinity War, but it just doesn't hold up as a well as other franchises, where later films do not require the rest to stand on their own - e.g. Back to the Future, The Dark Knight trilogy, etc. People who haven't gone to see every Marvel film may be lost, and those who I went with didn't have any investment in some of the characters.
I would also give the film a lot of credit for balancing the characters as well as they did, but having characters who are very light hearted , mixing with those who were quite dark, and jumping between them felt disorientating. Ultimately this was the curse of the MCU expanding so much, but other films have juggled multiple groups of heroes' quests much better - e.g. The Lord of the Rings trilogy.
Hulk's disappearance was also poorly done. Though I understood that being beaten by Thanos would have reduced his confidence, it doesn't fit his character in the past. When Thor blasted Hulk in Ragnarok, Hulk simply became angrier that he was losing. Hulk also refused to come back, despite Thanos not actually being there - referring to the last fight - so why didn't he come back then, when he knew he could beat one of Thanos' henchmen. Also, when the Hulk lost to the Hulkbuster, nothing stopped Banner hulking-out again. The film only needed a brief dialogue between Banner and Hulk, so explain why the Hulk was afraid to come out. It's absence irritated me, and undermined the character.
Finally, Thanos' quest has been overdone in the past, and didn't carry the same weight, due to more logical alternatives being easily plausible within the film. For the former, the (now exhausted) plot of the villain wiping out huge numbers of people, for the benefit of those who survive, is an easy way for scriptwriters to justify their villain's actions. However, Thanos needed something more original. Batman Begins and Watchmen are both relatively recent superhero movies, that had this plot (though in the first, the villain fails, and in the second, the villain succeeds). For me, this narrative became stale after the first Kingsman film did it. Now for the latter, the powers of even only half of the infinity stones, would undermine Thanos' entire plan. The abilities of the reality stone, means that it can transform matter. Therefore, it should be able to transform any 'waste' matter, into food. This would give the universe far more longevity than just killing half of its occupants, and would be better morally. Thanos would be more than capable of this.
Though the film was great fun, and I would definitely recommend it, Thanos' objective is incorrect and pointless, Hulk is essentially removed from the film with no explanation,it has some pacing and tonal issues, and the CGI monsters was bland. Although many of my complaints will be seen as nitpicks by the average movie-goer