"Good game." - Federation Trooper
Metroid Prime Federation Force was wrongfully panned. If you have someone to play with, it's lowkey one of the most fun 3DS games (I mean it's Next Level Games, they make good stuff).
And while I may feel a few of Next Level Game's games overstay their welcome, I didn't get this feeling with Federation Force despite being fairly lengthy because every mission throws something new at you. For example one of the late game missions has player 1 in their mech, while the other is de-meched for most of it. So p2 is defenseless and has to be protected by p1, but p2 can go into small tunnels and stuff, so it's a new dynamic of teamwork explored solely in that one mission.
The game structure is not Metroid, it's mission based and linear, but for what it sets out to do, it does very well. It's a neat co-op adventure with a lot of variation in mission objectives. And it has the Next Level Games silliness with the cheesy voicelines you can make your Federation Trooper say. The game is also surprisingly challenging, even before unlocking hard mode.
It's a shame no one played it, because of preconceived notions or whatever.