Challenge progression

1. Gameplay Difficulty vs Player Skill Level (Gamification Player Progression Tips)
2. Game Advancement vs Player Advancement (Gamification Player Progression Tips)
3. Player Abilities vs Player Powers (Gamification Player Progression Tips)
4. Player Advancement vs Player Improvement (Gamification Player Progression Tips)
5. Game Progression vs Game Advancement (Gamification Achievement Systems Tips)
6. Game Balance vs Fair Play (Gamification Achievement Systems Tips)
7. Player Goals vs Game Goals (Gamification Achievement Systems Tips)
8. Player Performance vs Player Progression (Gamification Player Progression Tips)
9. Replay Value vs End Game Content (Player-Centric Gamification Tips)