As one last fun bonus, Blast Rush LS Custom lets you play LS Mode using any bomb with any ship!
First unlock Blast Rush MD, then complete these criteria in any order:
Play Blast Rush MD once (finish or get Game Over)
Fire each of the 9 bombs in LS Mode. This means:
LS Mode Standard, Endurance, and their 2-Minute variants are valid
The bombs must be fired at least once
Finishing the mode is not necessary
Any bomb(s) you fired beforehand already count
View the entire Credits roll (reach the final screen with the copyright, then back out)
Return to the main menu and you should see the notification! A "CUSTOM" logo will also be in the menu and on the title screen.