I know old pc/laptop can lag, maybe if you try the compressed version, I think they resize videos and so, making it lighter.
Viewing post in Genex Love 1 (0.9.96) (Complete) (NSFW +18) comments
There's one in F95, not sure if it will work better for you.
https://f95zone.to/threads/genex-love-v0-2-11-reboot-love.109949/page-11