A long time ago after HDD crash a lot of files was recovered but some of them was unable to fully recover so they are corrupted. Is it possible to open them? Actually main problem is the main orchestra score sheet (probably the largest file in archive). I've also provided some extracted parts which wasn't corrupted, for reference.

http://andreyshuvalov.ru/files/polunin_corrupted_finale98.zip 

I tried to open .MUS in hex editor to find source of problems by comparing it with non-corrupted file but I couldn't make it.

Thank you.