Project Hail Mary appears to be a contemporary science fiction story built around the familiar premise of a mission intended to rescue Earth, or several planets. Along the way, the main character encounters Rocky, who proves to be an agreeable companion and helps keep the mood relatively upbeat, though this serves as a diversion from a narrative that progresses through increasingly improbable events. The sudden loss of everyone else on board seems deliberately arranged, seemingly just to create a close relationship between the two leads. A succession of fortunate accidents allows for a resolution that’s exceedingly positive. Initially, there seemed to be an emphasis on science, specifically the protagonist's belief in life forms not based on carbon; Rocky’s existence does confirm this idea, but the movie doesn’t explore it further, so a notable thematic element remains unaddressed. It is generally enjoyable and occasionally funny, though ultimately it doesn’t stick with you. The film provides entertainment while it’s playing, but there's not much to consider afterward.

Source on TMDB