that looks pretty good, but you really have to adjust the video's .
If this is for a portfolio you should put them all together in a compositing software package like combustion or something more simple.
Then use a format like quicktime and a lower resolution maybe, few people will download 250mb like that, you could easily take it down to about 50 mb.
You seem to be quite motivated that's very good, what you should now try is get away from the standard max tutorials you've been doing and start doing your own, more complicated projects i think.