It's aimed at anyone who want to make a parser game and there are no particular expectations about quality (or content, or length) so long as the rules are observed. The better the quality of the game, the higher it is likely to be rated.
Of course! Any parser game is very welcome, on any subject, from any author with any level of expertise - within the bounds of a few simple and sensible rules. The more diversity the better.
So if anyone is hesitating about entering the competition - please do go ahead and enter! And feel free to ask any questions you may have.