This game is not finished yet.
In the first alpha version, the version that is actually available, you can play only Eppisode 1, but in the final version, there will be 24 eppisodes, so, why I relased an incomplete game? Because I don't wanna make people wait, like what I done with Saigo No Hoshi, I want that you can immediately have a taste of the game, this mean that a lot of new patches will be relased (I hope), and you can follow me into developing :)
The first eppisodes are easy, but going forward, they will become harder and you will find new weapons, new mini-games, etc...