Multiple Questions from a new player

[Phredreeke]

I don't see a spell called Telekill. In one of these replies someone described it as a technique. Can anyone elaborate?

You teleport in front of the enemy, then strike it. Sorry for the poor explanation, I usually play rogue.

In recent discoveries in my unfolding saga with this game...I found that I could start a new game and keep my same character with his armor and level and stuff (yeah!)..Found that the stuff I'd left laying on the ground disappeared (oops!)...found that the dungeons have been restocked with monsters and items (yeah!)...but that killing the monsters in at least the first 6or 7 levels didn't give me hardly any level up points (sigh..)...but now I have more gold than Midas and several of my spell levels are advanced so we'll see.

You get 10% less for each level you are above the monster. So if you're 5 levels above the monster, you only get half the experience. At 10 levels above the monster, you get no experience. This is a bad thing with non-Hellfire Diablo, you can't go directly to Cats, Caves or Hell in a new single player game!

A couple more questions..
What is a "trainer"? I saw this in some posts and gather that it is illegitimate or something but what...

Very naughty (at least in multiplayer), can do a lot of stuff, from importing items to make you plain invincible. This of course takes no skills, so you'll quickly bore of the game.

What is a hack or a mod?

Mods are modifications to Diablo, usually to make the game harder.

What is a "legit" game?

A game played without trainers, duping and abusing glitches (such as using ms with low life to avoid being stunned)

Edit: Gah, too slow...