Paul Woakes‘ classic first-person ‘tank’ shooter Encounter was released simultaneously on the Atari 800 and C64 in 1983.
The Atari version is slightly chunkier and more basic-looking than the C64 version, but plays exactly the same. It’s futuristic tank-based warfare, with fast-moving 2D graphics. It’s retro-gaming gold!
More: Encounter on Wikipedia