The Hives, the hives, bug holes aso are a mechanic from the Game, which you can love or not. Depending on the enemys which spawns from the holes you stand there and hope your units kill, them fast enough or you have the right eople for the job, to finish the hole fast so you can kill the others and...

When multiple Spitter Bugs attack the same target (let's say a turret), they tend to make a circular barrier that holds other bugs that are coming. That's a very common issue in the mission Gatekeeper. My suggestion is to remove the collision of Spitter Bugs with other units. It's common to have HMG...