To be fair, Jet Force Gemini is from the popular company (or rather, they
were popular in the N64 days) known as Rareware, creators of classics such as Perfect Dark, Banjo-Kazooie, and the Donkey Kong Country games. Jet Force Gemini was a one-hit-wonder of theirs, and quite frankly, I don't think they ever gave it the respect it deserves.
The game itself involves you running around as either Juno, Vela, or Lupus, and engaging hordes of insectoid "Drone" enemies in frenetic run-and-gun action. Your mission at first is simply to open up the way to Mizar's lair, as he's ruthlessly conquering world after world, and the Federation (i.e., the good guys) don't see him as enough of a threat to sic the main military on - despite clear evidence to the contrary - so your team pretty much acts outside jurisdiction to smack him down. It gets more complex later on, but I won't spoil that.
Gameplay mechanics are about as good as any 3rd-person shooter on the N64 is bound to be: controls take a bit of getting used to, but once you've got those down, the action is quite fun and fast-paced. It has a healthy mixture of classic weapons like the Machine Gun and Sniper Rifle in the mix, but also throws in more unique bug-busters like the Tri-Rocket Launcher and the Plasma Shotgun. The enemy AI is actually quite well-made for such an old title, and there's a plethora of stunning alien worlds for you to explore. The only real gripe I have with the gameplay is that you have to do a
LOT of stuff just to reach the final boss (won't spoil the details, but I'd say you need practically 85-90% completion just to reach the last area)...but when you do get to him, the game makes sure you work hard for that ending.
And in compliance with this being an image thread, here's a screenshot from the game.