@matana retrospective is thinking/talking about something that happened in the past; looking back on it. That's why you'll see video game retrospectives on YouTube.

Retroactive is when you change something that existed in the past because of new things that have happened since then. Laws applying to crimes retroactively, for instance, would mean that if there were drug laws before and you were incarcerated but they changed them to where you wouldn't have been, if the new law is applied retroactively you would be released from prison.

So, game devs changing something about a game would be a retroactive change, for instance the whole Bridget thing. Retrospective would be like the game devs saying "hmm maybe Bridget should have ended up as a woman" but not actually changing it.