Hosting this game for the Speed Bump bounties show (http://speedbump.run) and thought I should give it a few real tries to make it challenging! Played on emulator. This run is not deathless; there is room for improvement still!
Tech:
*Avoid grinding as much as possible, especially hearts
*Largely ignore most small enemies, boost off of them
*Use the $1200 sword, collecting money quickly in stage 4
*You can skip a section of stage 5 right at the start
*Bring orbs and beat the 6th boss with them while he's slightly off-screen. I lucked into the 5-power orb for the fight
*Freeze the final boss in place by jumping in coming right