But that's half the fun~!

I think the devs fully expected you to have the full loadout by Zone 3, because by GEEZE, you'll need it.

Hence why I said "Expert Mode" instead. ;U

There's actually an option in the controls menu to assign "combo" controls (like DOWN + RIGHT) to other buttons! So you can set it so that, instead of pressing DOWN + LEFT for your bombs, you instead press L1. Or B. Or LB. Or whatever alternative you'd be using on your controller of choice.

"And while the game punishes you for failing to keep tempo, it will never kill you outright."
.. Actually, I'm pretty sure one of the later "Expert Mode" characters does EXACTLY this.