they did a nice job on the code.
it does work - there are things we liked and things we didn't like. first what we liked - you can have multiple users and also there is no database. now what we didn't like - it is not at all easy to integrate into pages, also once you place the code and includes onto a page, if you leave that page - every time you go back to it you have to login again and again (no cookies).
but for a very basic login script it will do fine.
also - they write good clean code.