Reviews

This is a fairly dark single-episode addition to Grisaia that does a great job of explaining Yuuji's horrific past (likened to the protagonist's childhood in Fate/Zero's). It also sets the stage for what is to come in the second season. It is told from the current time frame as a reflection of Yuuji's past in order for him to get a promotion. After exploring the protagonist's dark past, the episode finishes with a brief scene with the main TV show's heroines. The title image here is a bit misleading as it explains the events prior to the title image, you don't see much of Yuuji's interactions with the master that he keeps referring to in the TV series, as would be implied by the title image. Definitely a worthwhile addition for anyone who watched the TV series.

Animation:
The animation is on par with the main show, it is still presented in a widescreen format and uses the same color scheme and character designs. If anything, expect even more intense action and mature emphasis.

Sound:
There isn't an OP but a pretty energetic ED post climax. The VA cast is identical to the main show.

Story:
I mentioned a good deal of the story above already. In addition, you'll get a lot of Kazuki's background as well as the bishoujo principal. Yuuji's training under the (pedophile?) terrorist Heath Oslo is also explored in depth. It's a pretty dark, but engaging story (if I haven't said that enough already).

Character:
As mentioned, there is a great deal of informative and well-presented development in this OVA.

Value:
If you've watched the main show, this should be a no-brainer, a lot of the important context may not make sense without the background from the prequel.