Super Probotector: Alien Rebels, which is better known outside the PAL regions as Contra III: The Alien Wars, it's a video game produced by Konami in 1992 for the console Super Nintendo Entertainment System.
This is the third game in the series Contra to appear on Nintendo consoles, after Contra and Super C for NES. Set in the future, precisely in the year 2636, Super Probotector sees the previously defeated alien invaders return to the charge with a global-scale attack aimed at conquering planet Earth. The American version of the game maintains a futuristic setting even though the characters of the first two Contra, Bill and Lance, have been replaced by Jimbo and Sully. The game is beautiful and exciting but rather difficult, so a few tricks certainly can't hurt.
Note: this trick only works if you are using a turbo controller.
When you get to level 3, advance until you get to the mini boss "The Flying Squito Nest". Make sure you have the machine gun as your weapon, otherwise the trick won't work. Place your character at the left end of the screen, facing right. Press and hold the Y button and activate turbo mode. If you wait a few seconds you should have infinite lives (even if the count still stops at 29).
Contra III The Alien Wars - Konami