I'm not a dev, but I love the game and all, and yes, it's not quite a bullet hell, but the gimmick I think is not that the beams are slow, but that a lot of the tanks can shoot their beams at once.
The charger (the creature that rushed you) is actually something I enjoy, since it makes sure you're moving if you're taking the tanks out to fast.
I would like it more if there was a damage cool down, that would make the game much easier to get into, but I think it's doing well, and it seems like you never got to the hive barrens, which had a more annoying tank that instead of shooting beams, throws globs of dirt.
Thank you for reading my rant, not trying to attack you, just giving my opinion.