Feel free to enter here the bugs you just found.
Diff algorithm
Very simple, needs a lot of improvement as it is far from only showing minimal differences.
Anchor
They are created but I see no way of accessing them for now.
Update : it does seem to work. Have a try to this page.
Update2: make them appear. i.e, modify WikiRenderer's conf to output <a name="anchor">anchor</a>, instead of just <a name="anchor"></a>.
Images
Only local images are allowed for now. Do a treatment on URLs to allow external images too.
Email notifications
Filter out the modifier of the page. ie : do not notify the person who has modified the page.