You're spot on with the cheese, it's just looping around the whole screen. The secret is that I'm somehow able to take the cursor outside the the play-space entirely (not playing in full-screen). No bullets can me touch me out there but the cursor's trail is still registered somehow. So I can complete the loop at no risk lol
To be fair, it's much more balanced when playing by the rules. Just as easy to lose HP as it is to get back to full.
Seems like a Close Knit 2 is in the plans huh?