I think this has been my best attempt yet.. only the 2 last bosses got by.. the flying one wouldnt have if i had the 2 swarm bases upgraded a little more, he had less than 100 left.. the lvl 48 boss is just insane.. I did tho have him split in 2.. Only lvl 47 creeps and 48 boss made it to/past the S portion in the bottom middle of my map. My ending score was 3495.