5 - Animation 6 - AI 7 - Networking 8 - Networking (real-time synchronization) 9 - Networking (many users) 10 - Serialization and asset management 11 - GU

5 - Animation 6 - AI 7 - Networking 8 - Networking (real-time synchronization) 9 - Networking (many users) 10 - Serialization and asset management 11 - GUI and settings 12 - Custom in-editor tools 13 - Optimization part 1 14 - Optimization part 2 15 - More rendering 16 - More AI 17 - ??? You have a lot more 200-page books to go. Also this is just game development, you also need design, publishing, promoting, legal, etc.