All of the music in this game comes from Pyotr Ilyich Tchaikovsky's "Swan Lake", although some is modified; hence, the Weavers turning into swans, and Bobbin visiting the lake of swans when he ventures outside the Pattern.
The instruction manual promises an extra scene if the game is played through in expert mode. This extra scene occurs when Cobb removes Bobbin's cloak. We can now see what happens to Cobb, rather than it happening offscreen. In the CD version, this scene is included in all versions.
A CD version was issued, featuring higher quality graphics and music, plus a 30 minute "audio drama". However, the rights to this version existed with Mindscape, not Lucas (supposedly, LucasArts did not have the means to produce a CD-ROM title at the time), and were lost permanently when Mindscape went bankrupt. While Loom as been reissued since, it is always as the original floppy version.
The improved graphics from the CD ROM version became the baseline for the Turbo Grafx 16 version. The enhanced soundtrack was also present on the TG16 port. Copies of the TurboGrafx CD are still found for auction at the usual sites, but require the CD player component for the Tubo Grafx system.