Contra/Versions

Arcade
The game was originally developed for the Arcade in 1987.

In this version, the snow field in Stage 5 was combined into one continuous stretch to the end of the game. It also is more difficult if the player is either doing well or farming enemies for points.

NES
The NES port was released in 1988 by Konami. It included the "Konami code", which allowed the player to start the game with 30 lives, and also allowed a few continues if the player ran out of lives.

The NES version has a non-lethal bridge at the beginning of the level, and makes the corridor run easier by removing the left/right turns and the timer.

Commoodre 64
The Commodore 64 was ported by Ocean, under the name Gryzor. As with the arcade version, you had to complete the corridor section within a limited time (set to 40 and 55 seconds respectively.)


 * The firing rate of weapons is significantly reduced. However, you move faster compared to the NES version.
 * Stage 1 requires you to advance directly to the door before it becomes vulnerable.
 * The boss fights at the end of the corridor run were split into separate stages.
 * The waterfall stage is shortened in one of the two Commodore 64 ports, and the boss is replaces by a simple base.
 * The final stage starts with the Snow field, and is a continuous run. However, it is shortened significantly.
 * The spike claws in Hangar are replaces by electric barriers that turn on and off. You need to run through them as enemies appear on screen.
 * The final boss is only protected by mouths, and doesn't launch spiders.