Metroid Prime: Federation Force.
The fan idea of a Metroid FPS spin off game where you play as Galactic Federation Troopers has been around since the MP2/GCN era first showed off their existence.
What we got was:
>a 3DS spin off title
<released 6 years after the previous Metroid game Other M basically killed the series (or 9 years for the last good Metroid game, Prime 3), unlike Metrod Prime Pinball spin off release which was during height of Metroid GCN/GBA/NDS releases in the mid 2000's.
>has chibi like graphic style which producer Tanabe stated was for visual clarity on a handheld
<despite Hunters existing on the NDS (a decade earlier) just fine
>play as chibi troopers piloting large mecha suits against equally sized up Space Pirates
<to compensate for this plot hole, lore can be found saying that the pirates found "Amplification beam" tech from the ancient Bion race to make up for this bizarre player/enemy size inconstancy
>can be played 4P online co-op experience that can scale down difficulty if a player drop/leaves the group (unlike EAD's TLoZ Triforce Heroes)
<no voice chat for communication, just 4 simple preselected phrases at a time (probably better than Triforce Heroes emoji's)
>story has the interesting point that the player is the one that stole Metroid eggs from Space Pirates to get them into Galactic Federation hands setting up Fusion and possibly Prime 4 with Sylux cameo at the end of FF
<no one cared since everyone brings up the final boss battle being the Federation Force fighting a giant Samus in Morph Ball mode and defeating her while leaving her under a pile of rubble,
>has the 3 on 3 VS mulitplayer soccer mode Blast Ball, can even be played with AI players that are pretty competent and the game can handle online players dropping and replacing them with the AI bots
<this mode only exists instead of a standard deathmatch mode so players focus on shooting a single target (the ball) instead of shooting each other (which you can still do), even then it feels like a beta and has only one arena
>released on the 30th anniversary of Metroid
<final boss battle is basically shooting Samus in Morph Ball form while playing Blast Ball hybrid, happy 30th anniversary Samus your fucking dead! Because at Nintendo we only care about popular series anniversaries like Mario and Zelda! Metroid's anniversary is in the same year as Zelda, well bugger off then!