The video game preservation community argues that when a commercial game is no longer sold, and no modern alternative exists, downloading an IPA for personal archival use is ethically distinct from pirating a current title. However, you should always:

Here's some content regarding the LEGO-R Scooby-Doo Escape from Haunted Isle:

That said, original purchasers of Escape from Haunted Isle (or those who own the physical iTunes backup) are on safer ground. The “R” variant’s modifications (e.g., removing DRM, adding new text) are derivative works, which require permission from LEGO/Warner Bros.