Benjamin Devasir’s review published on Letterboxd:
It's been done before, but perhaps the relationship between the child and the alien / animal / non-human-cute-talking-thing has not been done as well in ages. The film takes up a big chunk of time establishing the character differences of Tip and Oh, but they also subtly drop in how similar they are as well. The pay-off is then well deserved, and you really feel for them when there is strife or turmoil that interferes in the amazing relationship the first hour of the film constructed.
Oh, and the entire bit with the 'interrupting cow' joke was amazing, and very well-done. Jim Parsons and Rihanna were surprisingly great together.