I was able to do a few more things before the submission deadline:

• Bug fixes on unlockable racer, clamped boost maximum and HP Maximum floats.
• Confirmed that Unlockable level is winnable, it is possible to beat the high score and unlock the extra racer.
• Character bios and one illustration were added to the Extra menu.
• My wife provided additional voice acting as a second announcer.
• More announcer triggers were added to additional levels.