Depending on where in the game you die, the color the words "GAME OVER" are written in will differ.
Depending on how long it took you to complete the game, you will see a slightly different ending. The endings differ in the attire you will see Samus in at the end of the game.
If you continue after the credits, you will start the game over with certain items/weapons retained, as well as not being in the Power Suit.