Hope that you are ready for one more incredible adventure with Phineas and Ferb while playing this exciting Down Perry-Scope game! The two smart brothers have started another amazing summer project involving a submarine, but they need to use it in order to stop Dr. Doofenshmirtz`s evil scheme with Agent P`s help, of course! They are eager for you to join their dynamic team and assist them in the battle against the forces of evil. Phineas and Ferb have built a brand new submarine and they are currently testing it out in their backyard lake which is disturbing their sister Candace who is trying to sunbathe and relax on her airbed. However, the smart brothers and their secret agent pet are on an important mission and they come out as winners! Help Phineas, Ferb and Agent P stop Dr Doofenshmirtz`s cunning plan of capturing all the fish from the lake with his evil suction vortex device and selling all of them to get a huge profit by descending Agent P from the submarine to the bottom of the lake so he can collect the sponges from the crabs and use them to clog the vortexes up! You must be extremely careful and focused at all times because this mission requires a lot of skill and precision. Use your left and right arrow keys to tilt the submarine up and down. You need to make all the right moves in order to win! You should use your spacebar to change the direction of the submarine when you consider it necessary. Use your down arrow key to drop Agent P to the bottom of the lake and grab the sponges or drop them into a vortex when you get close to one. You have to protect the fish and clog those vortexes up really fast if you want to save all of them! If all the fish are sucked into the vortexes, the game will be over. Avoid rocks, mines, and jellyfish because they are dangerous and can get you further away from your goal.Also, try not to disturb Candace because you don`t want her to find out about the secret mission and tell her mother! Use your up arrow key to inform Ferb that he should press the button to release the gas from the engine if you want to attain a higher speed.