Teenage Mutant Ninja Turtles/Versions

NES
The NES is the first version of the game.

DOS
The Dos version was part of a series of ports to home computers. It is the most infamous because it is unwinnable. It runs on most systems during the time of release, supporting CGA, EGA and Tandy.

The Dos has the following changes:
 * Leonardo and Donatello vertical attack ranges have been reduced.
 * All turtles can remain in their attack animation indefinitely by quickly moving left or right.
 * The rollers on the surface only inflict minor damage rather than being fatal.
 * Most minibosses are removed.
 * Like the NES version, items replenish when you leave the building or sewer and re-enter. However, the free pizza slices in the Area 1 are more difficult to harvest.
 * In Area 2, the approach to the final bomb has fatal coral at the bottom. However, there aren't any damaging weeds in that section.
 * There are no continues, but you can save your game. Saved games retain the health of the turtles.
 * The game runs at 10 frames per second.
 * The game is unwinnable unless you use a cheat code: The sewer leading to the stage boss requires an impossible jump because of a low ceiling and extended gap.

Sinclair ZX Spectrum
The Sinclair ZX Spectrum version has a smaller view area, allowing for enemies to attack with slightly less warning.

The following changes are notable:
 * There is no mercy invincibility, but damage is dealt a bit more slowly.
 * The pizza heals to full health, and you can find your first slice before the first fight against Rocksteady before he crosses the river.
 * Turtle attacks have no lead-in swing, displaying only one sprite.
 * Regular enemies are more easily defeated. Damage to them is indicated by an explosion, even if the enemy survives the hit (e.g. as with bosses.)
 * Surface enemies tend to wander rather than track down the turtle.
 * The dam level has a much lower time limit, but only has electric barriers. Damaging weeds and fatal coral have been removed.

Commodore 64
Compared to the NES version:
 * You get 4 credits instead of 3.
 * You can grab ladders mid-jump.
 * As with the Dos version, it removes the damaging plants on approach to the final bomb in the Dam, but replaces it with the fatal coral.