Being a movie (albeit a made for TV one!), the 1996 Doctor Who film had a larger budget than the TV show was used to. As such, they were able to use different effects for the regeneration scene. When the Seventh Doctor died after exploratory surgery, his body was sent to the morgue. Due to the Earth anesthetics used in the surgery, his regeneration was postponed for a few hours, but the regeneration itself was something never seen in Doctor Who, complete with lightning and face morphing effects. It's alive!