Impressive
Here I point out what I think are the bads and goods of your movie...
[BAD: ]
1. Maybe the simplicity of the graphics. Guys have pointed this out. But if that's because you didn't have enough time to do nice backgrounds, I totally understand. And even though they were simple, they were nice too!
2. The text in before the whole movie. Maybe you could have inserted some animation or still images around them... just my suggestion so that I can not only read the text but view some images of the 4 robots... etc
(just my ideas)
3. Some robot designs are a little too simple. But I like the Fire cyborg!
[GOOD:]
1. A hell lot of people seem to like it!
2. I bet you got an awesome score for this assignment.
3. Music was good and I think it suits the movie.
4. The animations (intro, text, credits, battle and all) was damn impressive.
[My rating: 6 stars]
Rock on!