Here is a new 2600 game by Natanael Vasconcelos called Cave Rescue.
In a distant human colony, aliens made a surprise attack, they destroyed several of our cities and the people who survived to such an attack took refuge in caves in the hope that something or someone come and save them and quickly, for apparently the aliens are approaching!
Your mission is to find and rescue people, to find them you must explore the five caves and defeat a specific alien in each of them, once this is done the position of the survivor will be revealed. After the rescue, you will appear in the next cave to make the next rescue.
Be sure to watch out for enemies and cave walls, as if touch them your ship will be destroyed, also watch your fuel (bar on left side of the screen) every time you advance in the cave or shoot it is drained.