Bliss Stage: Ignition Stage (2007)

From the Publisher's website:

Seven years from now, humanity is in ruins, devastated by a ferocious alien occupier from the edges of our understanding. The adults of the world have been undone by the aliens’ seduction, and the future of humanity is now a slowly dwindling population of child survivors.

But there is still hope for humanity’s future. A small group of survivors, led by a still-waking adult, have managed to reverse engineer the alien remotes, and have used this technology to make a new generation of weapons that can be used to strike at humanity’s enemies in their world of dreams. This weapon is called an Alien Numina Inversion Machine — or ANIMa — and it allows a teenaged pilot to enter the dream world and form a mechanized battle-suit out of the spirits of her friends, lovers, and enemies. With this weapon, she can fight the aliens on their own terms, striking at the very heart of their occupation. Now, after seven years of despair, this brave group of soldiers are striking the first blows of a war that will determine the fate of the earth, humanity, earth, and their own hearts.

Bliss Stage is a role-playing game for 2-7 players ages 16 and up. It is focused on the story of a group of teenage resistance fighters battling an alien occupation that they cannot comprehend armed only with the power of their own hearts. It is a love story, a war story, a coming-of-age story, and an action story all rolled into one.

This story takes 4-8 sessions of play (about 16-35 hours) to finish. The game is highly customized, though, and thus is different every time you replay it.