So I swapped over to my PAL C64, and I see the same issue! Well, the score gets to 75, but otherwise the same. I've tried loading it from an EF3 and from an SD2IEC. I have no other accessories connected.
Viewing post in Flangry Bird 101 (C64) by Prince / Phaze101 comments
The reason why this is happening is because it is written with an old version of TRSE. Will need to be converted to a new version of TRSE since it won't run just by importing it. However there is no guarantee it will fix this. Nothing against TRSE but it is one of the reasons why I stopped using it, not mature enough. Really thank you for going through all this trouble and letting me know.