Finally got to finish Level 4: Viridian Forest. I hope you guys enjoy it. Also now you can exit the game by pressing your phone's back button on the main menu, no more force closing :D
UPDATE: The last 3 Pikachus are the 3 you see in the beginning of the level, they never get to a weakened state so they are impossible to catch. But you can catch any pikachu besides those 3. Happy Hunting.