Yes, it's Planzet, not "Planet Z"
Planzet is a 2010 CGI movie by the same writer/director of Negadon: The Monster from Mars, to which this film bears many similarities.
Taking place in the near future, Earth has been ravaged by mysterious aliens known as the FOS. Although the planet is now protected by a "diffuser field", an operation to strike back at the enemy, known as Planzet, requires the field to be shut down while the secret weapon is being prepared, which will leave Earth defenseless. It's up to three giant robot pilots -Taishi, Ken and Kaori- to defend their base, with the fate of humanity hanging in the balance.
Tropes:
- Action Girl: Kaori; she holds her own in combat until she runs out of ammo.
- After the End: Partially; Earth's polar icecaps have been melted by the FOS and most cities burned. Civilization is collapsing, but still struggles to survive. The military have the best resources.
- Better to Die than Be Killed: After the D-cannon fails, Captain Yoshizawa tries to commit suicide but Taishi stops her.
- Big Brother Worship: Played with; Koyomi loves her bother, but is (correctly) afraid that his obsession with revenge is consuming him.
- Colony Drop: The FOS strategy when losing to the Super Robot.
- Deus ex Machina: A literal one. No, not the big ray gun. It turns out there was a hidden Super Robot in the Tokyo base, because it was considered too dangerous and was to be used as a last resort. Taishi and Komoyo stumble on it mostly by chance.
- Dwindling Party: Only Taishi survives the FOS attack.
- Tecnically Koyomi and Captain Yoshizawa also survived but they were barely involved in the battle.
- Fun with Acronyms: PDFA stands for Planetary Defense Forces Alliance.
- Godzilla Threshold: After nukes fail to stop the FOS, the PDFA is forced to resort to a Wave Motion Gun and later to a Super Robot.
- Heroic Sacrifice: Ken's.
- Iron Lady: Captain Yoshizawa. Daughter of the military leader who saved Earth from the FOS years ago, she feels she lives in his shadow and comes across as unemotional.
- It's Personal: Taishi is obsessed with avenging his father's death.
- Landmarking the Hidden Base: The Japan PDFA base is located inside Mount Fuji. It comes complete with a self-destruct system and a hidden Super Robot.
- Little Stowaway: Koyomi sneaks into the PDFA base without warning- just in time for the attack.
- Mood Lighting: The film is mostly colorless, probably to fit in with the grim atmosphere (and probably also its retro style.)
- Old Soldier: Ken is older and more grizzled than his fellow pilots. He's also a heavy drinker, but just as courageous in battle.
- Planet Spaceship: The FOS base is asteroid-sized and literally orbits the earth like an evil moon.
- Real Robot: There's only three, and they have limits such as running out of ammo.
- Retro Future: Like Negadon, the film is an intentional throwback to old sci-fi tropes.
- Short Film: About 50 minutes long.
- 20 Minutes in the Future: Set during the early 2050s.
- The Unreveal: We never see the FOS, nor learn why they wanted to destroy humanity.
- Wave-Motion Gun: The D-Cannon, the new weapon to be used against the FOS. However the diffuser field must be lowered first, it takes 14 minutes of prep, and can only shoot once.
- We Have Reserves: Apparently the FOS don't care about sacrificing their minions for the cause. they block the D-gun using several of their own ships as a shield.
