Joust is ok, I don't own one though. Gravitar is just too hard, I never could get anywhere with it. Tempest is probably my favorite game of all time, my high score of 374k that I set around 20 years ago is still on mine. It's one of those games where you get "in the zone" and the world around you just fades away. Another of my favorites in my collection is Quantum, it was not popular at all when it came out and is quite rare because of that, it's a really unique game though and with a Motorola 68000 CPU it is quite powerful compared to the 8 bit CPUs used in most games of the era, it is the only vector game capable of drawing solid objects.
Asteroids is easily the finest example of fully utilizing the capabilities of a monochrome vector monitor, the dynamic range is incredible and the gameplay is quite good too, the physics is absolutely top notch, it just feels good to play.