Dr. N. Gin is the fourth boss from the fourth warp room in Crash Bandicoot 2: Cortex Strikes Back. He is and the only one who was working for Dr. Neo Cortex and has 5 lives unlike the previous bosses, and can be considered challenging in comparison to them.
Crash is on three platforms. N. Gin, controlling a robot, comes in a window and says "Like Dr. Cortex said, give the twenty Crystals you've collected to me!" and the fight begins. Crash can throw Wumpa Fruit at the robot. A few seconds later the robot fires a red laser from its arm that goes up and down throw your Wumpa Fruit at the two arms when ever the opening is opened. Once you've gotten rid of them N. Gin will just have three hit points. Now, flaps on top of the robot's shoulders open and missiles fire up out of its head and hit down on the platforms. Hit the two of them with Wumpa Fruit and N. Gin will just have one hit point. If N. Gin has two missile launchers, two will get launched on the arena. Once on the left side and once on the right before repeating. If N. Gin has one missile launcher, he will fire a single missile for Crash to jump over. This time, the robot will go down, pop up, and blast the platform Crash is on with a green laser making it fall. Throw Wumpa Fruit at the chest. The robot will blow up, sending N. Gin out of the window and into space shouting back "Master Cortex will be very displeased with your resistance. Prepare to suffer his wrath!".