Because this is an unofficial .rar file from third-party sites:

: Parallel versions of existing levels with higher difficulty.

: If you downloaded this from a "free software" or "abandonware" site, ensure the community comments verify the file is clean.

: Rovio no longer supports or sells this version, so use it at your own risk regarding software stability and security.

: Archives of this type are frequently used to bundle adware or trojans. Run it through VirusTotal before opening.

Based on the date and file naming convention, this archive generally includes: