I truly enjoyed all those small hints from past episodes, such as the salty hot chocolate that Manny was so obsessed with in the first ever episode of the season, the things that Gloria finds in the drawer that links to other past episodes (such as the bebe gun from Manny get your gun), to the video clip of course.
I thought that this added an extremely nice touch to the episode, that instead of making Gloria find random, irrelevant things in the drawer, she finds all those items. Or instead of showing random video clips, they showed clips from a whole range of past episodes.
This is what makes this a truly special season finale, something that I haven't seem much of in other shows. Overall, a great way to end the season, albeit a simple storyline. This episode definitely deserves to be rated much higher that it is right now.