13 Things You Didn't Know About Friday 13th Part III
6. The Movie Might Answer An Important Question About Part 2
For a variety of reasons, the Friday The 13th franchise (at least in the early going) specialised in oddly ambiguous endings. However, there's always been a question hanging over the ending of Friday The 13th Part 2, more so than any of the other entries in the series.
At the climax, Jason bursts through the window behind Ginny, dragging her back with him in slow motion as Paul looks on, horrified, from the door. The scene then fades to white, and cuts to the next morning. Ginny is being loaded onto an ambulance, alive and well, but Paul and Jason are nowhere to be seen.
Interestingly, Friday The 13th Part 3 spends the first five minutes recapping the end of Part 2, but doesn't include the window attack scene at all. Instead, it shows a brief scene we haven't seen before: a close-up of a seriously injured Jason, unmasked and lying on the floor of his shack, stirring, dropping the bloody machete and dragging himself away. The news bulletin that Edna watches a few minutes later shows Ginny being loaded into the ambulance.
The implication is clear. Friday The 13th Part 3 retcons Part 2 to show that Paul and Ginny escaped with their lives, while Jason crept off to lick his wounds.
This further implies that the window attack scene has been retconned to be a dream sequence, just like the final scare at the end of the first movie - regardless of screenwriter Ron Kurz' protestations to the contrary.