Mediocre at best. Its watchable which is why I don't give it a 1 star.
It completely lacks all of the good that the first movie had. The first movie you can go back and see all of the details that lead to the final conclusion whilst watching the film but this one when explaining how Benoit Blanc came to his conclusions it just shows a completely different series of events than shown earlier to explain his reasoning.
The first half of the movie shows one set of events (through Benoit's perspective) but then in the second half it is revealed that he is actually working together with another character (Helen Brand) and then shows her perspective which adds a lot of context to scene we saw earlier. This is supposed to be a sort of big reveal, however, it felt like the whole first half was pointless as they just didn't give the full context before which you are then given in the second half.
All of the characters are annoying/irritating and make some incredibly stupid decisions. For example, right at the end of the film Benoit and his Helen find the evidence to prove the killer guilty and they just hold it out in front of them and pretty much just let the killer burn the evidence.
Another small detail that frustrated me was right at the end of the movie after the killer burns the evidence Helen starts to rampage inside of the house and destroys a lot of art pieces in the house. She then starts running towards the Mona Lisa and everyone tries to stop her but it is done so awfully that it just looks ridiculous with one character trying to dive tackle her and visibly getting his arms around her but then just seems to let go for no reason because of the plot.
The ending was incredibly unsatisfying as well as all of the detective work that Benoit explains, doesn't feel all that solid, with the final speech gives is all a lot of "He did this" "She did that" with not a lot of evidence behind these claims.
Then the movie doesn't end with instead of the killer being arrested, he had his public image and business destroyed which in my eyes isn't nearly as satisfying and as someone else pointed out in their review, the killer still has a load of money so most of the things he lost he can get back so it doesn't feel like justice was served in the end.