I could have gone on forever... except I picked up a damn singleshot again. I picked it up at the beginning of the "broccoli levels" (as I call them) when a broccoli died in my face. Somehow, I made it through the next three levels, but I was down to my very last life (second continue). I warped to the store, praying not to get Warp Malfunction. Then I got... fucking Warp Malfunction (surprise!). With singleshot, no auto-shoot, no bullets and no speed, there was no chance.
Final score: 714,330,555
Level: 1341 (or is it 1342? I completed 1341 and died on Warp. Can't tell - it's on the scoreboard as 134)
Money at death: $457,520
Meteor best: 647,200
Too bad. I was hoping to see what would happen at 1 billion.