Museum of the Second World War (Muzeum II Wojny Światowej) was opened in March 2017 midst open dispute between the Museum director (a former director now) and deputy PM/culture minister Gliński. Officially the dispute concerns the political message (the government insists on more patriotic education and more attention to suffering and heroism of Poles/Poland while the former director wanted a more universal message of horrendous sufferings of all involved nations.)
While generally I agree with the line of the former director I do not like/recommend the museum at all. It is very, very poor. And it is poor as it lacks interesting exhibits---which is more than visible from the very beginning (cf. photos). Lot of empty rooms, or huge showcases with almost nothing inside or boring stuff (everyday objects: spoons, plates, bicycles etc...). Many replicas/models, very often ridiculously small (ship 30cm long or a tank even smaller). Some stuff not particularly relevant (replica of pre-war Warsaw street or drawings from children competition "How you imagine a war")
In my opinion for a person with a decent knowledge of the subject visiting the museum would be a pure waste of time (and money---less important as the tickets are pretty cheap).