It was fun. 2 joysticks, one for each tread (forward and back). You could roll the tank using the joysitcks left right together, or turn the tank up by pulling the joysticks apart. The fire button was on the joysticks. Sounds weird but was pretty intuitive. I tried it emulated, even with 2 analog sticks it wasn't the same.
Tempest has the spinning nob. Centipede had the trackball. That sitdown helicopter game with the elevation control at your right hip. Or intellivision with that wierd 16 direction disc and the keypad. They don't work as well without. analog sticks help some (robotron for example).
There is also the chance that memory of those games has given them a more rosy glow. For example I can't imagine grinding up ulitma3 levels today.. But I did so fairly happily in my youth.
That, and emulation is just not perfect, and you can often "feel" when you're playing through an emulator and not the OG electronics.
The main thing I notice on the environmental version is the Sark voice acting, I still wonder if they actually got David Warner to do it. :)