The Game: As the pilot of a lone space cruiser, you must try to clear the spaceways of a swarm of pesky and relatively harmless drone UFOs, but the job isn’t easy. You can ram the alien ships with your ship’s shields, destroying them (but forcing your shields offline for a few precious seconds during which anything could collide with your unprotected ship and destroy you), or shoot them (which also forces your shields down for a recharge). To that screenful of bite-sized chunks o’ death, add an unpredictable Killer UFO that likes to pop in and shoot at you, and suddenly being an interstellar traffic cop ain’t so easy. (Philips, 1983)
Memories: I’ve been complaining about the small library of Odyssey2-games-in-new-clothes developed as Odyssey3 launch titles quite a bit, but here’s a game I can actually get behind. UFO is the combination of a strong game in and of itself, with a background graphic that doesn’t completely obscure the in-game action.
I’ve heard at least one Odyssey programmer state that the O3’s background graphics were required to be “tile-based,” meaning that only a small number of graphics could be designed and 
then had to be repeated (such as Pick Axe Pete‘s rocky “mine” backgrounds, or the game-spoiling “honeycomb” of Killer Bees). UFO seems to buck that trend, though – its background is asymmetrical, and more to the point, it’s dark enough to let the original game graphics stand out.
None of this changes the game play for better or worse, but this is a case where the background graphics actually do enhance the game by giving it a specific setting. The Odyssey3 version of UFO did see release in Europe as the Videopac G7400 version of Satellite Attack.