I don't have an iOS device, so I can't comment on the app itself.

The flavour the site's design adds is excellent. Major props for that.

I think it'd be cool if the background was `position: fixed;`.

I also really like the social aspect on the site ("Super awesome monsters created by our community."). I think a "monster of the day" would be an excellent way to get people motivated and involved (as sort of a competition).

Judging from the video, there doesn't seem to be an undo button in the app. Seems like one should be there.

Sadly, the site loaded slowly for me (~15 seconds; I'm on a low-bandwidth connection), and in that time, things were shifting position and some text was unreadable.