What makes a game good? Hell, what makes a game a game to begin with? I may not know the answers, but I think I can honestly venture some good guesses.
Assuming that you didn't leave after I devolved into some sort of nostalgia based lifeform welcome to the real meat of the subject: what makes a good game and to a further extent than that what makes a game in general. I will submit that I'm not some sort of expert who has played every game under the sun, but as I told you about yesterday I have been playing games for around 20 years now so of course that's included good games, great games, bad games, awful games, and even downright bizarre games (I'm looking at you Heiankyo Alien). And regardless of how well or poorly a game might go over there are at least a set of constants that I believe must be present to make a game good or to make a game a game to begin with.
First off, I believe that when it comes to a game there must be an end goal in mind. Sometimes this end goal is simple: beat the final boss, traverse the final level, etc. Other times it is a little more difficult to pin down. For example let's look at Wii Fit. Wii Fit is a game, but what's the goal? Simple, to get you into shape. The game itself does this by having you be active and keeping track of how you're doing.
A little more complicated than that of course are MMO's of any variety. Surely games like WoW and TF2 don't have a cohesive end point where you win, right? Well, yes that is the case, but I'd argue that in the case of the former you can play and experience everything WoW has to offer, and by beating the highest level boss currently available or doing things like completing every quest you do "win" the game, at least until the next large expansion or roster of achievements comes out. In terms of TF2 the goal is simply to win whatever match you're currently in, with perhaps a more overarching goal of increasing your skill to such a degree that you can play competitively and not be beaten. A lot of people will never make that goal, but it's not impossible, it's just not simple either.
I will grant you there are some looser cases. Take The Sims for example. Is there really a goal there? Well, maybe sort of. The goal is to let your little virtual person live the life that you want them to lead, and make the most of it before they die. Alternatively you can be a jackass and make their lives miserable, but that's a more player oriented goal. So the ultimate goal of The Sims is pretty much just "to live" and by doing so you're playing. Strange just how appealing that can be.
This brings me to my second point: investment of time. Even the simplest flash game is going to have a learning curve. It might be a tutorial level that lasts all of a minute or just the instructions on the title screen, but it is there. From then on it's about how much time you want to invest into the game. A game can get you to invest your time in a number of ways: by being challenging, engrossing, captivating, or a myriad of other things. However, and I cannot stress this enough, a game should never demand your time. This is a point that I'm going to be touching heavily upon later, as well as the first hint as to where I'm really going with this, but to digress.
Think of a game as asking for time, and how much time you're willing to give it is ultimately a reflection of how well the game is put together and how much you personally enjoy it. Some people blaze through titles and never look at them again, and that's perfectly fine. To them the game has served its purpose once they've seen it through to completion. On the other hand I know people who play games for years, doing things like speed runs, player imposed challenges and the like. One of my friends still plays Final Fantasy Tactics just to see what kind of party set-ups he can actually still beat the game with. There's nothing wrong with that either: if a game still brings you enjoyment then you still have every reason to play it.
This brings me to the third aspect of it: fulfillment. Fulfillment can and often does go hand in hand with enjoyment, although the two aren't always necessarily the same thing. Still, I believe for a game to be good, or to even be a game at all that it must be fulfilling. If a game is too easy than there's ultimately little enjoyment from the challenge derived from it. Note that this is different from simply becoming so good at a game that it no longer becomes a challenge. In those cases it is because you've enjoyed the game and found it fulfilling that you've taken the time to bother to master it in the first place (and if you haven't then perhaps you're just a little strange...). I believe that this is one of the things that makes the key difference between a good and a bad game. A good game will ultimately be a very fulfilling experience, while a bad game will not be. The reasons behind why this is so are as varied as the games themselves, it can be good or bad controls, story, difficulty curve, you name it. The point is that if everything balances together just right -- which is a hard thing to do -- then you get something that's worthwhile, and that's what a developer should strive to produce and every gamer should strive to play.
I'm not one to get too preachy, at least that's what I'd like to think, but lately it seems to me that there's been a growing trend, and not a good one at that. That some companies are producing things that I believe fly in the face of the three ground rules I've just set down. The how and why are things you might already be familiar with, but tomorrow I'm going to get right down to business and just tell you why I think that the shit Zynga and other companies produce simply aren't even games at all.