Regarding the UI clutteri-ness, are you referring to the flash interface or the webpage surrounding it?
UI, I'm referring to the webpage around the flash. It's a little hard for me to tell because I'm on FF2/Linux now and the site is kind of janky, these are some things I'd change:
- On the homepage, the buttons don't look like buttons.
- On the homepage, the way that the black line follows the borders of the buttons is ugly. Maybe it's the aliasing. If you're going to have that line at all, the horizontal should align with the vertical center of the buttons, instead of some arbitrary point.
- On the learning interface, the horizontal lines extending to the left of the flash are totally arbitrary looking.
- Too many thick black lines. Use contrast to control where the user's attention is drawn. Right now the front page goes logo -> description -> buttons/nav-menu (ignoring the video). Should be description -> buttons -> nav-menu -> logo. Part of this should include making the buttons and nav menu look more clickable.
Good: Everything that happens inside that beautiful white square. Stroke recognition, hinting, etc. The demo video is also good.