Difficulty is built into video games in a different way than in any other medium.

A movie may be difficult, conceptually or in terms of subject matter; it may be hard to understand or to enjoy. Yet all you have to do to access its entirety is to sit and watch from beginning to end.

Written words can be still more difficult. For these, you need a formidable mastery of language, concepts and context; you must convert text into sense. Still, the raw materials are all there for you to work with. You do not have to pass a tricky test in order to get beyond the first chapter. You won't find yourself repeatedly sent back to the start of a book if you fail. You do not have to practice turning a page at precise moments in order to progress.

Yet this is what the difficulty of many video games embodies: a journey that the majority of players will not complete, filled with trials, tribulations, and inexorable repetitions.

There's no one agreed-upon definition of a video game, or indeed a game, but Bernard Suits's phrase "the voluntary attempt to overcome unnecessary obstacles" captures a good deal of what matters. A player contends with obstacles according to a set of limiting rules—and does so, in the case of a video game, by entering a virtual realm that itself embodies those rules.

A good game is one that is rewarding to play, where the journey of discovery and incremental mastery is balanced between excessive frustration and simplicity. There may be many incidental delights, but without some measure of difficulty and repetition, there is no heart to the game, no mechanic inviting iterative exploration or breeding the complex satisfactions of play.

Yet video games are not only difficult to play. They are also difficult to write about and to discuss, and for related reasons.

For a start, they embrace aspects of many other media and disciplines: images, sound, music, text and speech, architecture and design, animation and modeling, interface and interaction, social dynamics and artificial intelligence. This brings a bewildering—and rich—load of baggage to a field that has only existed for around half a century. Like players, the would-be investigator of video games is often running in order to stay still.

Time is of the essence when it comes to almost every aspect of the field. Even the most difficult works of literature or philosophy tend to take at most tens of hours to read. Yet far simpler games can demand a hundred hours or more of play if they are to be exhaustively explored, while some online games raise the pitch of this expertise to thousands (hello, EVE).

Then there's the fact that games themselves don't stand still. With patches and expansions standard across the industry and player communities constantly evolving, many titles consist of a steadily updated environment and evolving social context. What does it mean to study the definitive version of a game or come up with a universal system of reference for research in the field? Are aging games to be understood in emulated form or on original systems? What does it mean to play a game outside its original context?

These are awkward questions. Yet addressing them doesn't just demand the exhaustive amassing of software and hardware. It also means paying close attention to the only place in which a game truly exists as itself: the minds of its players.

When writing well about almost any video game, authors are more like anthropologists reporting from the boundaries of a brave new world than critics dissecting a work of fiction. Their data is fieldwork, their analysis mixed with reportage, their most precious skills the arts of looking, listening, and recording. Simply Google "vanilla WoW" to find a trove of tales about the first version of World of Warcraft, for example— a vanished world of slow leveling and epic corpse-runs that now lives only in memory.

Similar reminiscences are everywhere in gaming, their genre somewhere between confession and myth-making. Talk to someone about even something as banal as Candy Crush Saga and the passions will soon start to flow: what levels they love or hate, where they're stuck, when and if they weakened and bought their way out of trouble.

Indeed, some games can touch us sufficiently deeply to be labelled an addictive hazard—and to suggest a special species of reverse-engineering, in which systems expressly designed to challenge and enthrall us become an extraordinarily concentrated chunk of experience. Set apart from actuality, games are a machine zone that can be refuge, meeting place, or unfallen Eden, and within which we are at once the heroes and narrators of our own journeys.

You can talk, then, about a game's art, politics, script, music, sounds, making, impact, legacy, sociological significance, and all the intricacies of design and data that conjure these. But you should never forget the fundamental contract every game seeks to forge with its players: accept this world and these obstacles in the name of experience, and make of them what you will. Difficulty is the point, not the problem. The play's the thing.

Tom Chatfield is a British author and commentator, most recently of How to Thrive in the Digital Age (Pan Macmillan) and Netymology (Quercus). Follow him on Twitter at @TomChatfield. A version of this piece first appeared in Early Modernity and Video Games (Cambridge Scholars Publishing, February 2014), edited by Tobias Winnerling and Florian Kerschbaumer.