I agree with Rinkuhero.

I think balanced elements, and an adequate diffculty curve are of great importance. Broken enemies/weapons/builds/etc. can ruin a game, and weird difficulty curves will ruin it.Don't matter where the difficulty curve goes, it must have a minimun of predictability to the player.

Right assesment of priorities. Set well your priorities of the game elements before making them. Wrong priorities lead to wrong results. Example: if the most important in your game is the ambient, set it as your priority, and when choosing, always choose ambience over other elements, like challenge. But be sure not to neglect those other elements, just make them secundary. 

Simple in-game explanations and a comprehensive help screen in the menu, or pressing F1 always work, except for a 4X ar some other overly complex game. The tutorial must be in parts, so more experienced people can skip pieces. If the player ignores all of that, it's his problem.

Also, my favorite card for what it does:

Amulet of Quoz is the same, but with the emotion of gambling!

Actually, it isn't good at all.

I can regiter trough the client, but not in the website, and from what I've seen, I need to enter the site for downloading or buying.

I still can't register, so Steam can suck my balls..

My favorite set is Tempest, it's for sure the best one. Then Urza's Saga and Ice Age are good too. Everything after Urza's is crap in my opinion. I never liked theme based expansions. Also, I nevel liked the way old classics weren't re-edited, classics decks like counter or sligh becamd art was better.

Some more favorites:

Fun fact: I own a black lotus.

EDIT:

Just saw this one. Great art, and a good sense of humor.

Two of my favorite cards, and two of my favorite artists.

RIchard Kane Ferguson is one of my favorite artists in Magic.

One of the classics and a personal favorite.

I started playing with a green/white deck with fifth, sometime vefore Tempest, and left after Urza's Legacy. Then began again sometime between Onslaught and Mirodin, with a counter deck, but left when I realized it wasn't the Magic I used to love, and that the new expansions where mostly crap. I still like to buy card just for the collection, some cards have great drawings. I want to get an Ebon Praetor and Stasis.

Monster-X took more tries than the final boss. But it's mostly realizing how to do it.

I only finished Cave Story once, with the polar star, and no hell. Started again, but I left it shortly, for some other game. The couple of times it made me angry and scream "This is bull****!!" really didn't add to replayability. <SPOILER>How is it that Dr. Booster dies if you talk to him, and why does the tow rope dissappears when he dies? That makes no sense! I can't overcome this kind of stuff.</SPOILER>

Single boss is good. It allows for lots of standard and crazy concepts. Also, I'm already making on of those now, but it would be cool to do another one :D

Honestly, I said I didn't like the sound of art game, but alternative, I feel repulsion for that one. While art sounds slightly pretentious, alternative sounds outrageously pretentious. It says that everything else is one thing and that alt games are completely another thing. It sounds like an effort to state that those games are something different, and stand out.

So, how often do you find yourself actually using the disk? Do you just install it once and leave it until next time your build a PC, or are the games designed to run from the disk? (which is probably a bad idea!)

Usually, never. I try to avoid using the discs. But actually my thing with boxed games is mostly a collectors thing. I've bought games that I've never played, just 'cause I could and I thought it'd be good to have them. I'm going to buy some game at some point, that doesn't comes in a box. The thing is that I get the feeling that I ain't getting much for my money, for as I said, having the physical game means a lot to me.

Physical presentation is a big plus in my opinion. I bought "This is a cry for help", and the few times I get to buy a game, I try to find some interesting game in a box, but I've never paid for a digital download. There is a huge difference to me between having a file, and having a box, with a nice cover, a DVD and maybe a manual.

How great is Doom II. One of the most important games from my childhood along with Dune II. But I only managed to win it this year. Some of the best character and level designs around.

:Bucket: I got you got a pig log dig dog turkey log corny cobb bag dang ding dong slap a dappy wiggy wam sex cow.

:Lucaz: what I'm supposed to do with that?!

:Bucket: You're supposed to know that, you're adopted.

:Lucaz: so, what about Cthulhu?

:Bucket: Ia! Ia! Cthulhu ftaghn! Ia! Yog sothoth! Ia! Ia! Praise to shub niggurath, black goat of the sea whorere.

You did well Chutup.

:Lucaz: AWESOME

:Bucket: Shut the fuck out of win and awesome.

:Lucaz: why don't go fuck yourself

:Bucket: I hate myself if you got me with fantastic accuracy the mass of a hooked jaw because that bitch was mouthy, she injected herself with 3 nigger nutsacks while reaching around minineo's mom's nike's while inverting the sum of the world fuck china fuck the jews causing 911.

:Lucaz: Cave Story

:Bucket: Charlie poltenson is a computerbased defense system, created by humans of the jewish race will not peel crawling in my butt? In my story.

A good interpretation of Cave Story.

:Bucket: Chaos is the key and the door.

I was teaching him about the Mythos. I'm surprised it made such a good phrase.

I've been looking for a game with bumping cars. I don't remember abything else, but fortunately there aren't much games with bumping cars.

Yep, Fool's Errand. I love that game.

Next one

My first game, is actually my only game. Curse of the Vampire, for MAGS, march this year. Just a short and simple graphic adventure, in black and white. That months contest was to make an incomplete game. Didn't do anything before, nor after.

Right now it isn't on the tubes, I'll solve that later. Actually, I'll do it right now.
Curse of the Vampire

It's Alley cat I guess. In that case... you know you already posted Alley Cat three pages ago, right?