Teenage Mutant Ninja Turtles II: The Arcade Game/Scene 4: Let's get to that secret factory!!

New enemies

 * Spear Carrier: these friendly guys can cause problems if you don't attack them as quickly as possible. They'll throw their spears at you from across the screen, and you can't deflect them like any other projectile. But don't get in too close, or else they'll jab you in the stomach, which could be some cause for concern.
 * Bomb Jack: you might get worried when you see a Soldier carrying a huge explosive device heading in your direction. Make sure they toss the warheads before you fight them, unless you don't mind being blown back by the resulting blast.
 * Motorcyclist: they're easy to throw off of their rides, but be careful if you're jump kicking from the front. If they do a wheelie, you'll fly right into the spinning tire.
 * Footmobile Red: make sure you stick to the extreme top or bottom areas of the screen when this thing appears or you'll become a hood ornament.
 * Footmobile Blue: same as Footmobile Red; you can choose to jump over the cars.
 * Footmobile Gold: flanked by Motorcyclists, this car is no harder to outrun than the others. Just make sure the ones on the bikes don't run you over as you try to knock them off.
 * Thunderbird: the helicopters can be overtaken with ease using a series of jump kicks. There are only a few of these, but if you don't pay attention to them, they can severely weaken you.

Santa Maria Highway
It looks like the turnpike is the quickest route to the secret factory, which hasn't even been mentioned by anyone, yet suddenly becomes top priority. The enemy groups are large and numerous in this remarkably uneventful stage. The Spear Carriers are rather troublesome due to the fact that you can't block the weapons they send your way. Try to Special them in close before they stab you with their quick thrusts. After both battles with them, you'll find cars, but just stay on the bottom to avoid them.

The three Roadkill Rodneys will still fall prey to the corner trap even though you're in the middle of the highway.

Watch out when the guys lugging around the missiles approach you. If you attack while they're holding them, they'll drop the bombs at your feet and you'll be injured. Jump around tauntingly until they toss their toys at you, then go in for the kill. Just after this screen (with the tire on the side of the road), a couple of Motorcyclists will patrol the upper half of the field repeatedly. No matter how many you take out, they'll keep popping back up. This is a chance to increase your score, if that matters to you.

The very end of the level has a few Foot Soldiers hiding in stacks of tires. You can knock the objects they throw right back at them. Here's a nice little oddity: if you jump over the thrown tire, then jump kick to the left and hit it just before it leaves the screen, you'll get a weird bouncing sound (like the snowmen made). Useful? I don't think so, pal. Not from me it ain't.

Uptown New York
Now you'll hop on some jet-powered skateboards for the second part of the trip. You control your turtle exactly the same as when immobile. The Thunderbirds that assault you before and after the meager groups of Soldiers aren't hard at all. Jump kick back and forth, timing it so you hit them just before they start firing the machine gun again. After six hits, they'll go down in a massive explosion. Don't hang out below them, otherwise the lower compartment will open and drop some unpleasant objects on you. Luckily for you, there aren't any Bosses in this stage. Of course, that luck changes as soon as you hop on the Party Wagon.