Later that year, August 1989, the game was released cartridge format for a US release. But during conversion Roger Rabbit had gone missing and the game was now being called Bugs Bunny's Crazy Castle. This means that all characters were replaced by those from the Bugs universe and the titlescreen of course had Roger replaced with Bugs.

Crazy Castle wasn't the original title for the US release though. The conversion was carried out shortly after the Japanese release and I happen to own a Kemco prototype from April 1989 containing a build of the game called Bugs Bunny's Fun House.

Why Roger changed to Bugs in the first place could be a license issue, Kemco might have only owned the rights for Asian Roger Rabbit release. In September 1989 Ljn released a Rareware developed game, called Who Framed Roger Rabbit, for the Nintendo Entertainment System, so Ljn Toys most definately owned the rights for Roger Rabbit at the time Kemco wanted to release it state side.

But why the title changed from Fun House to Crazy Castle is of course a bit of a mystery, other than it could've just been a normal step in the development process to tweak things a little, and Crazy Castle does sound way cooler than Fun House - which kinda sounds like a kiddie game to me, there probably isn't must more to the title change other than Crazy Castle sounding better.

With that said though, keep in mind that there was an american TV quiz show called Fun House that also received a NES version and this could be another reason why Kemco didn't go with the Fun House title, it could've been trademarked. Fun House the TV show ran around the time Crazy Castle/Roger Rabbit was released and the NES game was released by HiTech Expressions in January 1991.

While checking out the character set for Bugs Bunny's Crazy Castle it shows that graphics from the Famicom Disk System version is still present, such as "Please set side B" and "Now Loading".