Challenge Accepted: A closer look at Super Mario Bros.
It’s impossible for me to properly state the impact that Super Mario Bros. had on me as a youngster. I can’t say conclusively that it was the first game I ever played, although it might have been; I can conclusively say, however, that it’s the earliest thing that stuck in my memory. It was a remarkably long time before I owned an NES, so I remember playing it constantly at the houses of friends, including a few friends who may have been less “friends” and more “other kids my age with an NES.”
The down side was a number of visits that did no favors to my ability to socialize with others as a youngster; the up side was that I can go back to the game as an adult and re-examine it to find that yes, the game is pretty damn brilliant. It’s not an endless challenge like Tetris, but it does have a number of mechanical elements that make it a brilliant challenge, and chief among those is the one element of the game that no power-up can alter – the timer.
Challenge Accepted: Forever running

There is no permanent failure, just different steps on the road to success, most of which involve persistence.
When you play Peggle, there is a finite puzzle to solve in each level. No additional pegs will crop up to assail your dwindling supply of balls, you will not rush ahead to the next level with the same number of balls you began play with, there are no carryover elements from one stage to the next. You clear the puzzle as it’s presented to you and that’s enough.
When you play Lumines, this isn’t the case. The game starts, and it keeps going until you screw up. That’s the long and short of it. The challenge will just continue for as long as you play. And while both games are fundamentally puzzle games, one of them is a game wherein each level should be played to completion, while the other is an ongoing process. And there are some interesting differences between a challenge that just runs forever and one that exists in a contained space.
Challenge Accepted: Taking a deeper look at Tetris

Are there better feelings in games?
Tetris is, in every way, one of the simplest games ever devised. It’s also one of the most successful, perhaps the most ubiquitous game ever created. Everyone understands Tetris as a game concept more or less from the womb, and subsequent years have seen endless numbers of ports, adaptations, variants, and so forth. All based off of the very simple, straightforward, and almost trivial challenge – stack lines of blocks, don’t let the lines reach the top.
The simplicity of the game belies the fact that there’s actually a wealth and depth of challenge available in the game. It finds new ways to challenge you, perpetually, so that even though you’ve doubtlessly played the game for ages, every single game becomes a new challenge and something to be anticipated and enjoyed. It engages you on almost every level, and the result is a game that’s fascinating to both play and understand on a deeper level.
Challenge Accepted: I earned it

I have the tools to kill all of these orks, so I will kill them and get their stuff, because that is how this works.
In real life, overcoming challenges sometimes leads to rewards. Emphasis on “sometimes.” Sometimes overcoming challenges just means you’ve overcome a challenge. You climbed to the top of the hill, and your reward is seeing the other twelve hills ahead of you while you climb down this one. Or you climbed halfway up the hill when a falcon randomly deposited a sack full of money at your feet. How hard you work has some connection to success in real life, but it is not a perfect correlation by any means.
Games are not dissimilar. The notion is hardwired into gaming that a challenge equals a reward so long as the challenge was not completely self-inflicted (playing Metal Gear Solid one-handed is definitely going to be a challenge, but the game isn’t going to reward you for your determined efforts to make it harder). Yet there are challenges with rewards that seem either far too big or too small for the effort put in, because it turns out that properly balancing a challenge and a reward is really difficult.
Challenge Accepted: Perfect play

You could, in theory, program a Dan AI so perfect that no human player could touch him.
Here’s the problem with AI opponents: when programmed to win, they will win against humans 100% of the time in contests of skill.
I’ve mentioned before that there are four main avenues of challenge in games, but the computer easily bests humans in three of them by definition. A properly programmed opponent who wants to win has better reflexes than you could hope to have, since there are no manual dexterity challenges involved. There’s no problem of managing teammates or of remembering what’s in the game. There isn’t even much space for thought as an avenue of winning; it’s just possible to be smarter than the programmer and find avenues they didn’t consider.
AI opponents in basically every game are not tuned for perfect play, though. Even the hardest opponents need to give players a chance to win, after all. Perfect play is the flipside of having games be a series of decisions with some serving as better decisions than others, the idea of making all of the right decisions and having the dexterity needed to execute those choices properly and reliably. And it’s helpful to consider perfect play in the larger framework of games and challenges, and how much of it is, in fact, contextual.