This is a hard movie to swallow, especially if you don't know what to expect. It becomes quite sexy and disturbing at times, in a very peculiar way that only Almodovar tends to master.
All together, it is quite a good movie, but as a thriller, it lacks some elements that usually these types of movies have. You don't have the thrilling chasing scenes or the grand mystery behind it all. Just a man with a secret, a hidden lab and an experience.

Warning, may contain spoilers: By the end of it, I commented with a friend, how almost all Almodovar movies end up having transsexuals.