If you've come here, you are either a bit lost and looking for a quick summary, or you've been trained by years of bad web design to check About pages for contact information. Far be it for me to correct the Internet, so I'll add the contact stuff right after a quick bit actually about this website.
The Midian website is the full content of the game. I'll put it as plainly as I can: this is a tabletop roleplaying game. The game is played by you and your friends sitting around, rolling dice, and sharing a story. You already got the sales pitch on the front page and the preface. Those pages do a good job of explaining what the game is, albeit from the perspective of someone who already is familiar with roleplaying games. So, it might be easier for anyone who is confused to know what this game isn't.
This is not a video game. This is not a card collecting game. This is not a board game. This is not a miniatures/figurine battle game. You don't have to buy anything. This is not a video game. Yes, I repeated that on purpose; it doesn't always seem to sink in the first time I say it.
How is Midian different than other roleplaying games? It's the setting. We use a shared, dynamic setting. There isn't really anything unique or special about that, but we've done a good job of keeping things in order and keeping them fun at the same time. We certainly put in a lot of work doing so. You could do this with pretty much any game, but we already did the hard work for you. Your game sessions can affect the broader world, and in turn be affected by it. In a sense, it's almost like everyone who plays Midian is in the same campaign.
If you still have questions, contact me, Golgotha Kinslayer, on my message wall. You can post a question there without needing to login. We also have an entire forum board dedicated to just these sort of questions, with prompt answers within a day or so.