A sign in the lobby of Theater 555 says: “Warning: This performance features theatrical haze, flashing lights, and closeted Republicans.” And the set by David Goldstein that greets the audience is a gleefully tacky, Vegas-esque sea of silver tinsel streamers, with a “Make America SLAY Again” banner above. It all primes one for a good time. And then Five: the Parody Musical half-delivers.