Action progression loop
1st pillar
"The engine"
BASE GAME LOOP: Something fun and do it over and over.
2nd pillar
"The wheel"
PROGRESSION: A sense of progression. Same base loop but progression. Feels rewarding.
3rd pillar
"The road"
DIFFICULTY CURVE: Game gets harder the more you play. Complexity increases, difficulty increases, more challenges. Up until final test of all things learned to complete the game.