Great Conclusion to Avengers and Infinity War, but with Mistakes

Rating: 9/10 (28 April 2019)

Yesterday, I watched "Avengers: Endgame", and it's a great conclusion to the "Infinity War", and the most dramatic of the Avengers films. It was also surprising that a previous film, "Ant-man and the Wasp", although underwhelming, potentially kickstarted the vital plot of "Endgame".
Due to failed attempts to reverse the damages Thanos had caused, we see the likes of Iron Man losing his confidence, to the point of even shutting down ideas that could actually work (time-traveling in this case), and Thor eating and drinking himself into depression in "New Asguard" while playing "Fortnite". On the other hand, others like Black Widow were going around looking for Hawkeye, who was still angry over losing his entire family to Thanos' snap five years ago.
Then, Ant-man, having been trapped in the Quantum Realm for 5 years, which felt like a few minutes there, after coming to reality of what had happened during said 5 years, realized that one could weaponize the Quantum Realm to reverse Thanos' deed. This ends up being the main plot of "Endgame", as the goal of the surviving Avengers is to time-travel to various events of past Avengers and related films, and steal all ten Infinity Stones before Thanos could get them. They have to return the stones though, or else, according to the Ancient One, they could cause undesirable branches within the timeline, with Bruce Bender/Hulk (Bruce and Hulk are somehow fused together at this time-line) promising not letting such branch to happen.
In short: I liked the time-traveling mission, and how Thanos of 9 years ago through his Nebula managed to see the future through present-day Nebula, to the point of spying on the present-day Avengers, and launching an attack on their base after their mission. This paves the way to the climax, where the Avengers have to fight Thanos once again.
Before the attack, Bruce manages to use the Infinity Stones to bring back the fallen, who, half-way through the fight, with the help from Doctor Strange, join the battle again Thanos and his army. Obviously real-life, with heavy mix of CGI scenes, I liked how epic and urgent the battle ultimately felt on screen.
As a bigger spoiler, a handful of Avengers and Marvel characters never come back.
For starter, it looked like Thanos destroyed Vision for good while obtaining an Infinity Stone from his forehead in "Infinity War".
As we already know, Camora was sacrificed in "Infinity War" in order for Thanos to obtain an Infinity Stone. We never saw her since seeing her younger self at the end of "Infinity War", despite being on the same planet as where the Avengers found Thanos on in "Endgame". Maybe "Guardians of the Galaxy: Volume 3" might address this?
In "Endgame", the same thing happens to Black Widow while she and Hawkeye were fighting each other for the right to jump off the cliff... in order for the survivor to walk away with an Infinity Stone.
Since they're naturally radioactive, using the Infinity Stones nearly killed Thanos, as he explains at the beginning, with obvious injury on the side of his face. This causes Bruce to voluntarily use it on himself to bring the fallen back to life. But, in the climax, Tony (i.e Iron Man) urgently steals them back from Thanos, and uses them to end Thanos and his army. Tony is not as lucky as Bruce, and dies from his resulted injury.
From the resolution, the price being paid to bring the fallen back to life, and restore peace and order to the world, is realized, as the characters gather to mourn Tony at his residence. How the film ends, with Thor vacating his throne to fly to space with the Guardians of the Galaxy, really marks the end of an era for the current version of the Avengers. In short, I'd describe it as being "bitter sweet".
But, that's not to say that the film is without demerits.
The biggest issue is the time-traveling itself. The Avengers say to each other that changing the past won't necessarily change the future, as long as they don't do things that include meeting up with their past selves. That happens three times: Captain America, and Nebula interacting with, and even fatally shooting, her past self. Even Quill, in the process of finding that purple Infinity Stone, gets knocked out by War Machine, potentially causing the events of "Guardians of the Galaxy" not to happen. (Remember, in that film, Ronan's men were simultaneously looking for that Infinity Stone.)
In the resolution, Steve (i.e Captain America) time-travels to return the Infinity Stones back to their original spots, but is then revealed to have purposely returned to his original time to settle down with his old crush. This could potentially alter events and people till the present day. Many had even pointed out that Steve forgot all about Bulky. Let's say that he somehow found and reunited with Bulky in the past. In that case, the movie never addresses that. (He did hand his shield over to its new owner: Falcon.)
And finally, with help from Doctor Strange, the characters affected by Thanos return, but they apparently never aged, making them 5 years younger than they're supposed to be presently.
As a YouTuber, "Somecallmejohnny", said during his Sonic 06 review regarding Shadow: "Why time-travel? That's almost never a good plot device! If it's done incorrectly, which is very easy to do, s*** like this can happen!"
And also, the guys at Marvel Studio promised that Captain Marvel was going to be a huge part of the film. That honor goes to Iron Man as explained earlier, and even Ant-man weaponizing the Quantum Realm. Captain Marvel only ends up giving air support.
In short: It is a great, but bitter sweet, way to end the saga of "Infinity War", even the whole of "Avengers", as the credits show the name of the casts with their signatures, but no secret scenes. Just, don't expect this film to be 100% perfect all the way.