Low fps

[illgib]

I have alredy watched another gss before and all of them run pretty well, Age of Sails, Back to the moon, On ice, Pearl and Piggy, but Rain or shine, Son of Jaguar, Sonaria and Special delivery are completely unwatchable, very low fps, like 5 or 10 fps.
I don't really see why half work and the others none, and i don't see any heavy engine require for such simple scenes, so i don't really understand why they don't work.
Am i the only one whit that issue?