Choplifter!

The Good
It combined classic side scrolling shooting with search and rescue. You could also switch your perspective to drop bombs on enemies coming at you from the bottom of the screen. You felt like a hero when you successfully rescued a group of POW's and they waved to you as they got out of the chopper.

The Bad
The 4th level is just too hard. Navigating the caves is near impossible even without the enemy fire. If you can complete the 4th level you are a master game player :)

The Bottom Line
Your mission is to rescue POW's caught behind enemy lines. You fly your chopper into enemy territory, blast open the enemy camps to release the prisoners. Then carefully land and rescue the POW's. You must be careful when you have a chopper loaded with POW's because one hit and they all go down in flames. You must return the POW's to your home base.