Manga basic expressions

Here's a little practice with some VERY basic facial expressions found in manga. I basically used six times the same drawing, changing the mouth, eyes, eyebrow, and adding some other details.
Done for a research paper in ''intercultural relations'' (eurk...) were I basically compare american comics to Japan manga.

Tell what you think and PLEASE point any mistake in the expressions. The paper is due April 9th, so I still have some time to correct those.

Time: 2 hours (I'm so damn slow...)
Softwares: -Manga studio EX 3.0
-Adobe photoshop CS2
Tools: Wacom bamboo fun large