Like with any major comic book movie, Avengers: Infinity War couldn't please everyone with its first trailer. Of the criticisms that have been expressed, one of that seems to be of general consensus is that the visual effects work doesn't look as tight as fans have come to expect from a Marvel Cinematic Universe blockbuster - certainly not one of this magnitude. However, one fan is reminding us all to KEEP CALM and keep watching - Marvel Studios tends to get it right, in the end:
In the Infinity War trailer, shots like Spider-Man on an alien ship; the questionable color and tones of Thanos; or even the large alien army storming the fields Wakanda all look like they're not quite up to par, yet. However, as you can see above, MCU trailers never represent the quality of the finished product in full - which is really something loyal fans tend to understand at this point.
There's been overwhelmingly good (if not downright emotional) response to the Avengers: Infinity War trailer so far, so these kinds of complaints about things like unfinished visual effects should be taken with the appropriate boulder-sized grain of salt. From what we've seen, fans have every reason to be psyched.
Avengers: Infinity War opens in theaters on May 4, 2018. Thor: Ragnarok is now playing in theaters. Other upcoming Marvel Cinematic Universe movies include; Black Panther on February 16, 2018, Ant-Man and the Wasp on July 6, 2018, Captain Marvel on March 8, 2019, the fourth Avengers movie on May 3, 2019, the sequel to Spider-Man: Homecoming on July 5, 2019, and Guardians of the Galaxy Vol. 3 in 2020.