The Future Sucks 
...and unfortunately, you're living in it. Last year, after a rash of UFO sightings, the Sightless Monsters appeared. They could be an invasion force sent ahead to clear the Earth for occupation by some more advanced race. Or they could be the result of horrible experiments made by foolish human scientists. Or maybe it was radiation, or something. Who knows! The important part is, they'll kill and eat any living thing they happen to bump into. Anything not living (like, say, rocks, computers or cities), they just flatten and destroy. And though they can't see, and they're not too smart, they can sense movement from miles away.
So the last remnants of humanity are huddled behind sound-proof, vibration-proof barricades in what's left of the great cities of the Earth, trying to figure out a way to take their planet back from these hideous monsters.
Enter you. You're not the smartest person ever. But you've got a portable, short-range teleporter you're pretty sure you know how to use, a handful each of instaclones and high-energy shield generators, and a serious grudge against those hideous Sightless Monsters that ate a lot of your friends and even a few of your close relations. So get out there and save humanity. Because heck knows, humanity needs all the help it can get. Even from dopes like you.
Huh?
So, how do you go about saving the Earth? One step at a time. No, really. Every time you take a step, the Sightless Monsters become aware of your presence and take a step towards you. Luckily, they have terrible memory, and as soon as you stop moving, they forget where you were and just stand there. Also luckily, they're terribly stupid, and if they run into others of their own kind, they'll kill and eat each other. If they run into a dead monster body, they'll even try to eat that, but monster flesh is poisonous, even to monsters, so that kills them, too. But tricking the monsters into killing themselves isn't as easy as it sounds, so below are some items that will help you out.
Stuff You Get
This is a sweet, super high-tech hand-held device that you found in the remains of a building that the Sightless Monsters didn't quite get a chance to finish smashing. You have a reasonably good idea of how the controls work. Anyway, you found the "Go" button. There are some dials on there you think are probably used for setting the coordinates of your destination. So you just spin them randomly and hit Go! Wherever you end up, it's bound to be better than where you are now! (Note that if you run across more of these, it would be a good idea to pick them up. Even though you only really need one, you don't want the monsters getting their hands on them. They might figure out where the Go button is, too.)
Possibly your most important piece of equipment, the instaclone is a wonderful invention that some mad scientist came up with a few years back. A rich friend of yours gave you three of them when he heard you were heading out on this insane quest, and you hope you can find some more on your way. An instaclone, when activated, converts nearby matter into an exact copy of whoever activated it. You've got yours set such that, if you're about to be killed by a monster, you'll instaclone automatically. Some version of you will almost certainly survive! And hey, remember to get these as soon as you see them. If a monster gets one, he may not die as easily as he normally would.
After a little research, scientists discovered that only very high energy bursts can kill Sightless Monsters--in fact, not only do they kill the monsters, they totally disintegrate them. So people started jury-rigging various appliances and devices to give out extremely powerful energy bursts. What you've got are three shield generators. These were originally designed by the military to create a protective field around the user, so he/she couldn't be struck by various projectile weapons. Unfortunately, they were never meant to handle as much energy output as they're handling now, so whenever you turn one on, it only lasts for as long as it takes a monster to take a step toward you (and they will be stepping toward you, as the shield causes quite a lot of sound and vibration). So use them sparingly, and only when you're backed into a corner. If you manage to find more, make sure to grab them before the monsters destroy them.
Other Stuff You Can Do
Yodeling 
Wow, you never thought this talent would come in handy. But occasionally, you get tired of this whole one step at a time thing and just want those monsters to come barreling toward you all at once. And nothing makes the monsters come running faster than a good yodel. (Only use this talent if you're sure that all the rest of the monsters in the area will die if they keep running toward you.)
Portable, Short-Range Teleporter 
Instaclone 
High Energy Shield Generator