Cobra Command

Quite a good action game. The main goal of the game is to rescue all the prisoners. In addition to flying on the surface, you have to descend into underground bases after blowing up enemy buildings that hide the way down. Throughout the game the helicopter can be upgraded by landing in certain places. Quite difficult - you can fail to reach the next save bonus by 'kissing' the ground or a wall. Similar to Airwolf, but more dynamic. Mostly released on pirate cartridges under the name Urban Strike. The Japanese version is easier.