At the start hard to tell, but as you get going and start exploring alot more, Im mostley on the infinite maps ._.
Untill I am better prepared I usually just run away or around bases with rocket launchers >.> and usually never return to areas with 5+ of them plus turrents plus multi bases all in one giant cluster <.<
But after you walk by bases and dont destroy them, it seems on the attack waves its throwing the creepers on all "created" creeper bases. This tends to make a lot of lag when you have a lot of bases thier you havent destroyed yet. For some reason it varies what it lags, the whole game will lag or just the poor creepers <.<
Last map that did it I had 3 creepers spawn in the middel of no where it seems, took like 10 mins for them to reach my base, then i stood there and watched them move across the map area >.> for 2 mins <.< before i got bored of waiting for them to walk into my turrents and just blew them apart
![Razz :P](./images/smilies/icon_razz.gif)
Maybe add a little "active" to the bases? Like if thier is a base within X by X of the player, thier active bases all others are deactive or sleeping while spawning creepers only use active bases