Sentinel Worlds was the first game that I really got emotionally involved with. Just being able to start hacking your ship in the opening battle, watching stats go up as you are going around. It was a fun game, wandering around with that little blue dot rotating around, getting slowly better.
And then, completely out of the blue, they start throwing magic at you. My favorite was the power to make friends. "You're a friend, you're a friend, you're a friend!" Watching all those red dots turn into blue; which also let me move forward as they acted as a swarm of meat shields.
That revelation of something new is something that has stuck with me ever since I got the game as a holiday gift back in 1988.