As a little kid, I always loved this game and I still love it. This is fast paced action 2D Platforming at its best. The levels are hard, but not impossible.Controls are great, music is great and there's just a sense of Adrenaline in this game.
There are minor issues with the game. Duke walks really fast and the screen can't keep up, resulting in enemies seemingly popping up out of nowhere.
And also, I remember Duke not wearing any sunglasses. Those didn't came until Duke 3D. Why they decided to have the sunglasses on in this version is beyond me. Duke doesn't need the sunglasses to be Duke. I know it's a minor detail, but I guess you can compare to George Lucas changing minor things in the original Star Wars trilogy. It doesn't make it worse, it's just annoying.
But when it comes down to it. This is an excellent game and well worth the price.