Cool! Some of my thoughts:
1) Orchestral-Epic-Videogame-TV-Movie - I would trim out the first 15 seconds of intro as it's pretty subdued. Start the demo right about 15 seconds or so for the melodic part, especially since the following section returns to that more subdued, lighter texture of the intro. You want to hook the listener in and seconds count here. 15 seconds of intro isn't going to serve you as well as starting bigger then showing the potential client "hey I can also do restrained, more intimate, lighter stuff too."
2) Orchestral-Ballad - this is an interesting approach. I would caution against using the same theme, putting it in a different arrangement then labeling it another song in your demo. Instead, I would suggest creating a longer demo piece that shows how many different settings/arrangements you can put a single theme in. A collage of arrangements all using the same theme. It could feel like a small, nuanced thing, but I could see some clients going "huh... I just heard this!" whereas if you clearly set expectations/labeling it could be a neat selling point. I would suggest, however, doing more than just two settings of this theme. Some settings that come to mind - heroic, sad, large scale, smalls scale, as a march, as a boss fight, etc. Sit down and see just how far you can stretch this one theme.
3) Chiptune is fun!!! I'd just recommend having 2-3 more tunes you can highlight as a collage there because it will show more range in that style. As it sits, the song is on the repetitive side (not a criticism of the song) and you want to use every second you have the listener's ear to your advantage!
That's about all of the time I've got to review right now. A few quick other notes - I'd check the volumes of your pieces from song to song. Is it all about the same level? Or are some much louder than others? I think you're definitely on the right path. The music you have up sounds great - I'd just supplement these songs with more versions so you can show your range and flexibility within each style/genre.
I hope that helps!
Nate