Good but needs balancing
It's a very good concept, but it has some balance issues. It's near impossible to regain momentum for either side if you have a reset or two close together, anything you get out is just instantly splattered by a swarm.
The single use items are actually more of a hindrance than a boon a majority of the time. I'm actually happy to see when my opponent has a few of them, it's usually an easy win.
The last issue is a bit personal. My color vision sucks, and units like the berzerker and warrior piled together tend to turn into a blur, so a greater difference in appearance, or even color specific tiles behind would help a lot.