It’s not awful or easily dismissed, but it's also not particularly upbeat or cheerful. I have to admit I enjoyed this film, possibly because it resonated with me on a personal level. It centers around the pain of losing someone close and how one copes with suffering, which was difficult for me to watch given that I recently experienced such a loss myself. I had anticipated something lighter in tone and more joyful. That did disappoint me somewhat, and I suspect others will feel similarly. However, I can’t say I disliked what I saw. The story follows a young teenager navigating daily life at school and home while emotionally preparing for the impending death of his mother, who is seriously ill. Throughout this process, he begins to imagine a realistic monster that confronts him with his feelings and forces him to confront difficult situations, as well as strained relationship with his grandmother. Directed by J.A. Bayona, it’s a fairly ordinary film. The plot is foreseeable, the "monster-tree" concept has been used before, but it's generally a good idea, particularly when intended to be a wise and ancient being, as it is here. Lewis MacDougall takes on the lead role and performs adequately, even though the script doesn’t challenge him greatly. I also appreciated Felicity Jones’ performance, although she isn’t given much to do. And I feel bad for Sigourney Weaver; she's a talented actress who was miscast. It seems like a significant casting mistake—a genuinely British performer would have been more suitable than an American with a noticeable and artificial accent. From a technical standpoint, the CGI is certainly impressive and does a good job, especially during scenes where the tree comes to life and reveals its true form. The musical score was pleasing, even if it isn’t particularly memorable or inventive, and the cinematography is solid. Liam Neeson lent his voice to the monster; he's an experienced voice actor who has brought many fantastic characters to life in other films, making him a reliable choice for this production.

Source on TMDB