Truly excellent and perhaps the most 'intellectual' film by Forst, a film that's almost a meditation on the relationship between reality and representation. That goes for many films by Forst, but seldom more explicitly than here. Can we regard the 'bad' Willi as just a 'copy' of the 'good' Willi (which we most likely do when we watch the film)? Can the copy take the place of the original if no one can tell them apart? Especially as the 'bad' Willi is far closer to Forst's famous 'Bel Ami' persona than his slightly 'anemic' art-historian brother.
In any case, Frost's performance in both roles is magnificent and equally convincing for both parts. And while the sets are certainly more small-scale than in other Frost films, the same care and attention has gone into them, and the scenes in which both Willis appear together are done flawlessly.