For your first animation I think you did well. Sure, there is some stuff to work on and that need improvement, but I'm glad you actually tried to make a solid flash before submitting it to the portal. As a gamer myself, I can totally relate with this flash and GTA 5; I like when I can make relations during a viewing experience.
You can tell you have your own, bright style. Plus the movement animations of the characters mouths was good.
Voice acting wasn't too bad. It could use a little bit of work. More of preparation rather then quality. In other words you made it easy to tell that you were simply reading it, and that you weren't 100% ready before recording. Your animation is alright in some areas, but the lack of actual character body movement takes away from the flash.
A few things that you should work on for next are:
- Add a start/replay button.
- Practice voice acting. Really get into the habit of knowing your lines before recording (my opinion).
- More character animation.
With those tweaks I have a feeling your next flash will be 110% improved.
Above all great work, and keep practicing!