Played on BGB emulator version 1.5.9: https://bgb.bircd.org/

This is a run I didn't think I would get. I was hoping maybe to save 2-3 seconds, but a 6 second timesave is crazy. Great rng on the first two splits, and the later splits had enough enemy spawn to keep it alive. I think faster times are possible, but it starts to get even more rng dependent on all splits. combo counts each split: 1: 4 2: 16 3: 50 4: 54 5: 54 6: 52

Other notes: I was going for an 18 combo in the second split, but since I didn't see any nearby planes I stopped early at 16. This made the later splits even more difficult since I had so little margin for error, but I did it. I was nuts to go for a 54 on the fifth level, but I somehow made it.