i got most of these facts of the internet and other places.enjoy!

1.In the first donkey kong the charecter was orignally ment to be the villain bluto out of popeye but nintendo lost the licence so miyamoto changed it to a big gorilla
2.The orignal donkey arcade had four levels and at the end of each level donkey kong would grab pauline and climb upwards.At first miyamoto wanted it to be upward-side scrolling level but the circuit board couldn't handle it so instead he turned it into four screens.
3.Did you know that mario was called jump man in donkey kong?and did you know that he was called mr video even before that?but even before that he had yet another name "ossan"which means middle aged man in japanese