Muv-Luv: Alternative

Muv-Luv: Alternative is a 2006 Mecha Sci-fi visual novel developed by age. The story follows the protagonist of the previous two games, Takeru Shirogane, as he repeats the events of Unlimited with foreknowledge of what will happen, and attempts to use this ability to defeat the BETA and save humanity by enacting the Alternative IV project, all while trying to prevent the Alternative V project from being enacted.

Why It Rocks

 * 1) Gorgeous visuals, especially for a visual novel.
 * 2) This is the first time Takeru is seen onscreen.
 * 3) Takeru has a much more developed personality than before. While in the previous two games, Muv-Luv: Extra and Muv-Luv: Unlimited, he was a pervert who took virtually nothing seriously and is constantly berated for his inexperience in war, in this case, he's able to take things much more seriously while still having somewhat of a sense of humor, which makes him much more interesting.
 * 4) While it may seem like the events play out exactly like in Unlimited, Takeru is technically already trained to be combat ready, which changes quite a few things.
 * 5) Plenty of choices throughout that actually make a difference in the plot and how it progresses.
 * 6) Much more intense and emotional than the previous two games, as the BETA finally show up.
 * 7) Likeable characters, most of which are strong female characters (and alternate versions of characters from Extra that Takeru knows)
 * 8) Fantastic story. It takes the "Earth at war with Mars" trope and actually does something interesting with it, giving a lot of lore to the world with plenty of history before Takeru awakened and giving an interesting concept of alternative (no pun intended) universes as well. There's also plenty of politics in the world that make it so that there isn't an easy solution for the most part.
 * 9) While there's some fanservice, it's much more subtle than a lot of other series, not using it too gratuitously and not demeaning any of the female characters.
 * 10) Awesome depiction of Mecha elements, in that there aren't any that are overpowered, and there's limitations to both the pilots and the machines themselves.
 * 11) Awesome soundtrack.
 * 12) Sumika finally appears again, something that was teased repeatedly in Unlimited.
 * 13) For fans of Attack on Titan, Hajime Isayama cites this game as a partial influence.

Bad Qualities

 * 1) While the BETA finally appear, they don't actually appear until about three quarters of the way through the game.
 * 2) A MASSIVE tonal shift at that point that some fans weren't too happy about, notably for some "grotesque" scenes.