International Karate+ ?
HA, another game which had BETTER sound than the c64 on the A8:
http://www.youtube.com/watch?v=TwfgP7OtQG4Firestart Project ? No. Looks like Karateka graphics ?
Impressive shooting games...where to begin ?
....well Gyruss of course !!! Another superb arcade conversion...
http://www.youtube.com/watch?v=SA1PERH9i8Q(and yet another game that has better sound on the Atari than on the C64

(ignore the hiss on the video, that's not on the game))
And of course
Caverns of Mars (looks simple but is LOADS of fun, you have to enter AND exit the same tunnel_
http://www.youtube.com/watch?v=UwGSVzqLCg4&feature=relatedBlue Max of course.
Zaxxon was VERT smooth too, esp. compared to the Colecovision version.
Pooyan was great
Moon Patrol, great conversion !
And of course River Raid and my favorite 2600 shooter Demon Attack was also available on the A8 (almost identical, but never improve a brilliant product !)
Dropzone ! A great "Defender" like game, also much better on the A8...(compare the side to side scrolling on both versions...)
My favorite shooter would be Fort Apocalypse
http://www.youtube.com/watch?v=i67O3FkSGckAnd if only they would ever finish this:
http://www.youtube.com/watch?v=tmEFFp0lLzo&feature=relatedWell, it's not my goal to get into another "war" but I just want to show that the A8 was a much underrated system which was extremely powerful, so much that it could compete with a machine that was released 4 years later (and in those days, the leaps in technology were MEGA, compare Space Invaders (1978) to Star Wars (1983).....some period of time !!!!
The bottom line: the C64 had a better sound chip (but I didn't like it's USUAL tones(but some programmers got GREAT stuff from it !!!), and it only had 3 channels, compared to A8's 4 channels)
The sprites were also better on the C64.
But that's all. Everything else was less....

Atarimania: did you get your stuff ?!?!?!?
And also, can you help me remind me of a shooter on the A8 that was like Pleiads a lot, where the aliens would "capture" things from the bottom of the screen, and I seem to remember thee were some Apples in there for some strange reason. It had great sound and a lot of humor. I think I had to load the Translator to play it.
Some other brilliant games (not shooters) that jumped to mind:
Flip&Flop (if you like Q-bert, you're gonna love that !)
Drol !!!!
Mr.Robot !
Ollies Follies