The first few missions serve as an introduction to the game's mechanics and storyline, while the facility missions are where the game gets really challenging. The final showdown is the most intense part of the game, where you face off against the main enemy and his henchmen.
Restart the game, and all levels from "Trainyard" to "Finding the Bomb" will be unlocked. Bonus: In-Game Cheat Codes To use these, first type project igi 1 all missions unlock top