I made a mock teaser trailer for a game that I half made and that may or may not see the light of day.
I did it just for fun really and to practice editing things because I've never done anything like that before.

Elephant Arena Teaser Trailer - YouTube

It definitely has a few problems, most noticeably for me is the glow on the scoreboard lights and by the time I'd added the fade ins between shots I ended up with very little shot left, so the passovers at the start are shorter than I'd like but live end learn....