Edit: I got downvoted for this comment, but the author has made the change. My sacrifice was not in vain!

> - If your font colour is more thant #333 on white, you're being cruel, especially to those who suffer astigmatism.

A designer should think hard before reducing contrast. You may be improving the experience for one group at the expense of others:

- A low contrast page is difficult to read on a cell phone in daylight.

- A low contrast page is difficult to read at night on a dimmed display.

I don't meant to discount folks for whom high contrast is a problem, but don't they have a simple recourse? Reduce the brightness or contrast of the display. Most monitors and laptops have controls that allow this.

The colour gradient on the graph is confusing - does green mean happy, blue unhappy, and the movie changes tone over time? Axes of the graph are not labeled, what are we looking at? But, those concerns are secondary.

Bar graph seems a poor choice here, given the nature of the data. Given that there doesn't seem to be any correlation with time, the order of phrases doesn't seem important -- you could forgo the linear presentation, and display the distribution of the data instead.

For example, you could bucket the sentiment values (-3 to -2, -2 to -1, etc) and use a histogram to show the counts in each bucket. This would enable you to compare different movies (one histogram per movie).