The phrase " Megan by JMac: Megan Mistakes Repack " appears to refer to a specific community-made "repack" or modified version of a game featuring a character named Megan, likely developed by an entity or creator known as Based on the terminology used:

JMac’s scenes often feel more "cinematic" than standard loop-based animations.

JMac has hinted at additional content that will dive deeper into Megan's world. This includes new story arcs and character developments that were not part of the original series.

Do you need a guide on technically?

Repacks often include automated installers that streamline the setup process for complex directory structures.