Oh, you could make such a terrible Hollywood remake of “Key of Life.” The pieces are all there, just waiting for some hack screenwriter to mess them up.

But it hasn’t happened yet, so enjoy the dizzying original Japanese screwball comedy while you can, which had two screenings at the Wisconsin Film Festival this week.

The premise is classic high-concept comedy; wannabe actor and all around loser Takeshi (Masato Sakai) sees an opportunity in the bathhouse when another bather slips on a bar of soap and is knocked out cold. Takeshi quietly switches locker keys with the unconscious man, steals his clothes and cash out of his locker, and hightails it out of there.

Only it turns out that he has switched identities with a cold-as-ice hitman, Kondo (Teruyuki Kigawa). Driving Kondo’s car and living in Kondo’s fancy apartment, Takeshi is mistaken for the killer and roped into doing some unfinished business for the local yakuza.

The real Kondo, meanwhile, has amnesia, and settles into in Takeshi’s old sad-sack existence. But he’s happier than he ever was as a contract killer, especially after he meets magazine editor Kanae (Ryoko Hirosue) who has marked her wedding date on her day planner. Now she just has to find a husband, and Kondo seems as good as any.

Writer-director Kenji Uchida has written a crackerjack script, one with jokes that detonate right away and others that lay fizzing for most of the film before suddenly exploding when we least expect them too. At over two hours, “Key of Life” could have been a little snappier in the pacing department, but the energy level and inventiveness never flags, and when the comics twists and turns come along, they’re beautifully executed.

“Key of Life” was picked up for U.S. distribution by Film Movement, which bodes well for a DVD release.