DEFENDER Arcade Game
The game spawned lots of clones, including Dropzone which was released by Arena Graphics in 1984 for the Atari 8-bit and C64 computers. Dropzone won critical acclaim in most computer magazines of the day, including a gold medal in Zzap! 64 for the C64 version with a 95% rating. I remember playing Dropzone on my Atari 800XL and it was extremely responsive and a joy to play.
No, I'm not going to make a rude comment about the nice young lady firmly gripping that joystick.
Defender on the BBC Micro Model B and Acorn Electron
Ths BBC version was developed by Acornsoft and was a very authentic clone. In fact, it was too authentic for its own good and this led to the game being renamed Planetoid for legal reasons. The game was also released on the Acorn Electron, the budget version of the BBC Micro. Acornsoft were pretty brilliant at game conversions, and this is, without doubt, the best of all the home computer versions from the 80s, although the Atari 8-bit version runs a close second and has some excellent sound effects.
Defender BBC Micro Model B Screenshot
Defender on the Atari 2600
However, it has to be said that the Atari 2600 version was pretty dismal. There are numerous problems, the main one being that your spacecraft disappears temporarily when you fire a missile. Whether this is the fault of the hardware or the programmer is up for debate, although other games managed it with ease, so my guess is that the programmer was at fault. Aliens also flicker and are pretty erratic with their movements, too. The controls are pretty clumsy and I'm not sure how this game seemed to slip under the radar when Pac-Man and E.T. got such a roasting from the critics.
Defender Atari 2600 Screenshot
Defender on the Commodore 64
As with the Atari XL and XE computers, the C64 was a very capable and advanced machine for its time. Although not as refined as the arcade version, the game plays well on the C64. It looks a little crude, but this was one of the earlier C64 games and the graphics look more Hi-res than other home computer versions. The sound effects are excellent, and I also like the way the screen compresses and disappears to the right when you move up a level - a nice touch.
Defender C64 Screenshot
Defender Atari 800 screenshot