This is a demo version of Suikoden II that was bundled free with the UK release of Vandal Hearts 2 (I'm unsure if any other Europen releases included it, I assume so though).
Truth be told, to me I was more interested in this demo than the actual game when I bought it (not that Vandal Hearts 2 is a bad game, it's pretty good too), but as a massive fan of the Suikoden series this was something that I pretty much had to have. Especially considering the rarity of such 'freebies' of any sort in European releases/pre-orders.
As for the Demo itself, it contains 2 modes: Story mode and Battle mode.
Story mode will not be new to most folk who download this torrent (I'm guessing most who do will already be fans of the series), as it's basically a small segment of the start of the full game. As far as I could tell, it doesn't differ at all.
The Battle mode however is exclusive to this Demo. Again, it is a section of the full game, however it does deviate quite a bit by allowing you access to characters that would not be possible to recruit at that stage. It also features a changed script, involving Nanami being annoyed she didn't appear in the section of the Story mode that was included.
All in all, it's an interesting curio for Suikoden fans. I hope you enjoy it!