I bought this game a couple weeks ago and experienced the same lagging issues at the end of the first episode, and in subsequent episodes as well. While it's a terrific game, I feel that the issues plaguing it are awful and should be fixed. If that's not possible, I feel that PS3 users experiencing this should be awarded a code to download the game in full from the PSN store.
I want to play through the game again, but I don't want to sit through all of the hiccups . Playing through it the first time was almost unbearable. Please fix this issue.