So I was extremely pessimistic when I heard Tougen was coming out. But you know what, it's pretty good. It has good action, a decent story, and it really invokes the atmosphere from the first season of Garo. It's a lot more than just "a side story with the minor characters from Garo".
Thread / Wiki
Also, if you can play music, this is apparently the sheet music for Requiem for Heroic Heroes from Red Requiem which was included in the Tougen booklet.
Also also, there's two extra footage clips this time. Enjoy!