I always felt John Cusack was only in the first one because he was a staple of a lot of 80's flicks and he just so happened to star in anything for the money. Also, remember this line from the first one?
"If I wanted to kill myself, I'd fukking kill myself...I'd be awesome at it...a shotgun to the dikk!"
So he might've actually gone back in time to shoot himself in the dikk.