Whether it's taking part or just watching, there can be something encapsulating and engaging about a good game. But what makes a good game so appealing? While much of course depends on a person's subjective taste, it is worth considering what makes a game enjoyable, absorbing and rewarding.
First, what exactly is a game?. The concept of a game is notoriously difficult to define. In Philosophical Investigations, Ludvig Wittgenstein demonstrated that 'the elements of games, such as play, rules, and competition, all fail to adequately define what games are' [quoted from wikipedia]. Games and play vary so much that it is difficult to use a catch-all definition. Newman suggest that a common characteristic of games is that there is a rule-system that players must abide by. Without a rule system of sorts, a game ceases to be a game, and constitutes merely playing. Newman cites Callois (2001) and his distinction between paidea and ludus, referring to activities with simple and complex rules respectively. Simple play, say with a Frisbee, lacks the more complex rule systems of games such as rugby, or monopoly. However, there is a grey area between the two distinctions, as there in no real definite line when play becomes a game, and ceases to be just play. In addition, there are times when play is an inherent part of games, and some might argue that while games aren't always involved in play, play is an integral part of all games.
In his book Home Ludens, Johan Huizinga discusses the importance of play in culture society and learning. He proposes that play helps us to form a relationship with the object or person we are playing with. For example, infants are said to be 'playing' with something, when they are experimenting with the object's nature, getting to grips with what it can and cannot do. As Paul Feyerabend writes in his book Conquest of Abundance (1999) (Quoted by Kane) '[Science] is a bricolage of experimentation ... initial playful activity is an essential prerequisite for the final act of understanding'. In addition, Kane writes (in Chapter 2, The Play Ethic): 'The moment of play is identified as a generator of originality, energy and new development'. Hence play is an important and indeed necessary experience for infant and children's learning. Why not for adults too? The inclusion of play and playability engages the player, contibuting significant motivational allure, adding to much of the *appeal* of a game.
Aside from play, what else makes a good game? Competition is often a feature of games, and can be said to add a dimension of thrill to a game. Callois categorises the competition element of a game as *agon*, recognising this as a feature of many rule-based games. The agon element certainly motivates players. Competitiveness has been recognised as a biological trait, linked to the urge for survival, and is likewise linked to winning, a primary motivation for many game players. Thus a game may be more appealing to a player if there is a good chance s/he might win. However if it is too easy, this may prove to make the game seem pointless, and be de-motivating. [In contrast, some players may find that *collaboration* constitutes a more important aspect of appeal. The communication and relationship building that comes from joint effort may for some players be a real attraction.] Callois writes in his book 'Man, Play and Games', that 'the practice of agon presupposes sustained attention, appropriate training, assiduous application, and the desire to win. It implies discipline and perseverance.' These requirements for agon-based games are not only likely to increase motivation, but they are all learnings that are likely to be transferable in other fields, such as work, recreation, and even studying
However, neither competition and collaboration are entirely necessary for a game's appeal. Take Solitaire for example; there is neither competition, nor collaboration, but there *is* a challenge. And this aspect of challenge goes right to the heart of gaming of any sort. A game is not a game unless the proponent(s) is forced to resolve some problem posed within a certain framework of rules. Whether it's how best to stick a ball in a net when 11 people are trying to stop you, ot how best to invest your money into houses and hotels so others lose their money, games will always involve an element of problem-solving within a framework of rules.
And it's this concept of *challenge* that best answers the question what makes a good game? Newman describes Jessen's experiment (1995) who observed children playing Transport Tycoon, finding that 'working out the rules of a videogame constitutes a large part of the fascination and challenge and is a principle motivation for play'. He also cites Rouse (2001), whose identification of why players play games includes challenge and immersion. Although this study focused on videogames, the same could be said for other non-digital games too. People are intrigued by 'novel and exciting situations to experience' and are stimulated by the 'refinement of performance through replay and practice'. Newman refers to Danesi (2002) with respect to puzzle games, stating 'part of the appeal of puzzle games arises from the disruption of order' and the 'reinstating of the equilibrium state' and this resolution of a problem is what Rouse (2001) and Crawford (1984) 'identify as central motivations for play'. When we noticeably improve at something or figure out how best to do something it feels good. The satisfaction of working something out can be a strong motivator. If the challenge is too easy however, this feeling of accomplishment diminishes - likewise, too hard and a player may become quickly de-motivated. As Bernie de Koven writes, 'when the challenge is greater than our abilities, we become anxious and potentially dead. When the challenge is significantly less than that of which we are worthy, we become bored, and potentially dead'. So part of what makes a good game is a challenge that is tough enough to require improvement of skills/knowledge, but not *too* tough.
Rouse (2001) also mentions 'primacy' as a motivation for game-players, where the player gets completely involved in their actions. This aspect of immersement is key to a good game. And this primacy can also extend to avid observers of games, not just the players themselves, as diehard fans and followers of sports teams will confirm. (The dying seconds of a close match will feel like hours while at other times the observer may be completely 'lost' in the game.) This primacy state to some extent mirrors Csikszentmihalyi's 'flow state'. David Farmer quotes how it feels to be in the 'flow' state:
 Completely involved, focused, concentrating - with this either due to innate curiosity or as the result of training
 Sense of ecstasy - of being outside everyday reality
 Great inner clarity - knowing what needs to be done and how well it is going
 Knowing the activity is doable - that the skills are adequate, and neither anxious or bored
 Sense of serenity - no worries about self, feeling of growing beyond the boundaries of ego - afterwards feeling of transcending ego in ways not thought possible
 Timeliness - thoroughly focused on present, don't notice time passing
 Intrinsic motivation - whatever produces "flow" becomes its own reward
As Farley (2000) writes (quoted by Newman), 'good gameplay ... makes you forget yourself and the passage of time, not operating consciously but going with the flow'. Any game which is designed well enough to encourage this state in its players is likely to hold great appeal, and as point  mentions, becomes an important feature of its attaction.
So there may be many factors that combine to make a good game; some of these will depend on the players interaction with each other, some will depend on the game design and how the particular game develops. For educators, it is worth considering these factors when designing games for teaching purposes. Combining the play aspect with a challenge that is absorbing and engaging is a challenge in itself, but one which may ultimately prove very rewarding for all the players and designers alike.