Summary
Great Graphics Don't Make Up For Horrible Gameplay
The Good
Donkey Kong for the 2600 has surprisingly great graphics. Coleco did an excellent utilizing the consoles hardware to its fullest and making some relatively high-res graphics. For a console notoriously known for being graphically horrible, Donkey Kong is a nice surprise.
The Bad
The graphics don't make up for the fact that gameplay is incredibly difficult and frustrating. I understand input options are very limited on the 2600. The joysticks are not designed for platform gameplay. But response time on the button presses is slow, which means you have to time your jumps even more so than at the arcade. Otherwise it leads to a fit of rage involving chucking the console at the TV over losing your last life so close to the top of the level.
The Bottom Line
I'm not sure if the 2600 version of Donkey Kong in a true port of the original. It's a good attempt to bring the arcade game to the home console, but it's just not designed for this hardware. Nice try Coleco, but Donkey Kong for the Atari 2600 was not the same Donkey Kong from the arcade.