Yeah, the six sides is the most fun, it can get addicting when you get them (or atleast for me, i would sometimes just play and forget to work on the game)
you probably had frenzy, if you merge with an orange circle, you can ignore firerate for 5 seconds
the sound effects were made using rfxgen, made also by raysan, recommend it if u need a sfx sound generator
yeah balancing is an issue, everyone complained about, in development i would either make the game super easy or super hard, maybe i should have checked more balancing ways (i just thought of a wave system, that would have been nice)