It's a game about hitting things with particles. That's your one sentence elevator pitch right there. YOU HIT THINGS WITH PARTICLES.
And it works. To a point.
It's a really weird game because when it works, when your play and the game come together and you're spinning around this arena with your swarm of particles (hence "Swarm Arena") smacking the hell out of whatever comes your way, it feels tremendous. The way the music kinda syncs up with your actions and it feels like you're performing some sort of ballet of particle death and that, honestly, is really, really something.
But then you start to lose and a lose state in the game isn't quick and clean, it's the slow removal of your abililty to play the game as your swarm gets wittled down and wittled down. It's not quite a walk of shame a la Ridiculous Fishing, it's more that it seems like no-one could work out how to do this cleanly and fairly and just sort of went "that'll do". It wouldn't be such a big sin if it didn't drag the game out and into a state where it's just not, briefly, enjoyable to play. It's like your overriding memory of the last round isn't the bit where you're swooping round smacking everything with your particle army, it's the bit where you're trapsing around trying to keep these two particles going to get a few extra points. It doesn't even feel like clinging on desperately, just sort of "oh. well."
Nevermind though because Swarm Arena is worth it for the moments where you are THE PARTICLE KING and no-one wants to stop THE PARTICLE KING because THE PARTICLE KING has ALL the particles and he'll particle up your face. Or something like that.
Look, it's good except for the endgame bit, OK?