I used the Ctrl-# method to assign keypad numberz to each Grunt, top to bottom.
(It is perfectly acceptable to do it your way, but the walkthrough may not make as much sense.)
Area 1 The Snowballz playfield
Area 2 The Bricklayer's puzzle
Area 3 De-populating the enemy's barrackz
Area 4 Finger dexterity exercise #1
Area 5 The Reluctant 'Partner'
Area 6 The Big Central Lake
Area 7 Rockz are flying!
Area 8 The Brickyard
Area 9 Oooh! Bombz!
Area 10 Walled in ... or out?
Area 11 Walking on water
Area 12 Pyramidz everywhere
Area 13 The foot race (and aftermath)
Area 14 Let's Wing it!
Area 15 The new recruit
Area 16 The big split-up
Area 17 The reunion
Area 18 Up. Down. No up! This'll be tough!
Area 19 Free at last!
Area 20 The final battle
Area 21 Cross Over The Bridge(z)