Original System: Atari 5200
Ballblazer was one of the final Atari 5200 games to be released along with Rescue on Fractalus. Although both games were due to be released in mid-1984, the game crash and subsequent shake up at Atari delayed both games (along with Gremlins) until 1986. In the meantime the Atari 400/800 version was released on disk in mid-1985 and later on a cartridge for the XE line of computers in 1987. There's minor copyright and credits differences between all three releases, but the gameplay is exactly the same.
The main difference between the three is that the Atari
400/800 versions (both disk and cartridge) contain an animated
intro of two rotofoils chasing a ball that plays while the game
is loading. This isn't present in the 5200 version as
there are no loading times. This intro was kept in the
later XE cartridge version because it's a direct port of the
disk version and not the 5200 version.
The next difference is in the copyright text. The Atari 5200 has a copyright of 1984 and calls the game "A Lucasfilm Production" while the Atari 400/800 disk version has a copyright of 1985 and calls the game "The Lucasfilm Original". The XE cartridge release has a copyright of 1987 and calls the game "A Lucasfilm Production". The 5200 prototype calls the game "A Lucasfilm Ltd Production" and has a (c) in the 1984 copyright.
Another difference between the versions is in the
'certification' text. The 5200 and early 400/800 disk
versions say that Ballblazer is "Regulation Certified
Interstellar Ballblazer Conference", while later disk versions
and the XE cartridge version changes this to read "Tournament
Certified Interstellar Ballblazer Conference".
Interestingly the 5200 prototype says "Certified for Regulation
Play Interplanetary Ballblazer Conference".
Finally there are minor changes in the hidden credits between the two. The Atari 5200 version has simpler credits that appear all on one screen while the hidden credits in the 400/800 disk and XE cartridge versions have more descriptions and appear over two screens (see the screenshots below). The method for accessing the credits is also different between the two versions. In the 5200 version you must input 1,6,7,2,9,4,3,8 on the title screen while in the 400/800 versions you must type AUTHOR on the title screen.