Glad you're enjoying the game. Thanks for the compliments.
Either the Linear, Singular, Random A, or Random B mode can be selected when the cursor is in the "Start" position. SELECT, START, A, and B all act as buttons to begin the game, and the mode you activate will depend on which button you used to start:
SELECT - Singular: Play one Stage for the entire game.
START - Linear: Normal stage progression.
A - Random A: Play begins on selected Stage, every Stage afterward is chosen randomly.
B - Random B: Game ignores selected Stage and chooses random Stages throughout the game from the very beginning.
You can choose the starting Stage in "Start" mode on the title screen by pressing Up or Down to cycle through them.
The "brand new characters" I referred to in the manual are Pac-Xavier, Noxious Stinky, and Wayward George. Speedy Pinky and Bashful Inky are the classic characters who are returning. You can only play as Pac-Xavier, of course.
A manual speed control, you say? Hmmm...