Double Dragon NES Guide

Mission 1

Mission 1 is fairly simple.  However, many people go through it the wrong way.  Gaining hearts should be your only concern.  The fastest way to do this is by punching.  Use punches only on the Wills that come out.
In the next section two Lindas will attack you and one will be wielding a whip.  Use a single kick to cause her to drop the whip, but don't pick it up.  Finish them both off with punches. 
When you approach the Lopars, one will have an oil drum.  Avoid the drum by moving up or down when Lopar throws it.  Punch your way through the Lopars, but remember not to use kicks.  More Lindas will attack you in the next section.  Kick the one with the whip, and punch the rest.  You should have three hearts by now, allowing you to jump kick.
As soon as you enter this room, move up or jump kick.  If you don't, the Lopars will drain your energy fast with a few sucker punches to the head.  If you have earned three hearts by now, the Lopars will also be able to jump kick, making it a bit harder.  Punches and timed jump kicks will help you defeat them.
Now for some trouble.  Orange Abobo will come out, and he's ready for one thing: SMASHING.  Luckily, Abobo doesn't like conveyer belts.  If you are having difficulty beating him, make him follow you onto the conveyer belt, then jump kick to send him to his death.  Remember, you can fall too if you're not careful.

Mission 2

Mission 2 is a little more difficult, but it's also more fun.  You will be immediately attacked by two Wropers, and one will use a box.  Try to cause Wroper to toss the box at you.  Afterward, take them both out with punches and/or kicks.  The Wropers may use jump kicks, so punches might be a better solution since they tend to knock opponents out of mid air.
After the Wropers, a Will will attack you (ha) with a stick of dynamite.  Get just close enough for him to throw the dynamite, but don't let it hit you!  Instead, as soon as Will throws the dynamite, walk left to avoid it.  Then kick him when he gets close.
Climb straight up the fence and walk toward the Will with the baseball bat.  Immediately jump kick him to knock the bat out of his hands and land safely on his right side.  Don't pick up the bat; just beat him with your hands and feet.
Jump off the edge of the fence - don't bother climbing down.  Stay away from the ledge on the left while the Wills attack you.  Use the same technique described above to dodge the dynamite, then give the Wills some fists of fury.
Kick Linda to make her drop the whip, but once again, don't pick it up since you still need more hearts.  Punch the Lindas on the bottom level, then head toward the ladder.  Don't climb it.
Wait for the two Lindas to start climbing down, then jump kick without holding the control pad so you don't fall off the edge.  Kick the Lindas off the ladder so that they fall off the edge to the right.  Climb up the ladder.
Wait for the last Linda to start climbing down, then jump kick her off the ladder and finish her off.  Make sure to avoid the edge on the right.
Make your way up to the top to face Chin.  You should have four or even five hearts by now.  Kicks are your best weapon, but if you stand close to him when he is getting up you can land some good punches.  To finish him easily, you must have four hearts.  Stand above the ladder so you aren't too close to the edge.  Kick him till you grab his hair, then press A to throw him over the edge.  End of story.

Continue to Mission 3