What kind of games are music games?
In the context of Roger Caillois' typology, let's see to what extent music games are games of skill (Callois': agon), chance (alea), make-believe (mimicry) or vertigo (ilinx). Caillois in his Man, Play and Games distinguished these four aspects as mixed in play activities in different ratios. Music games are very diverse themselves, but maybe there are some trends to be discovered?
Game or play
Another axis of the typology: ludus (rule-based) and paidia (experiential activities) may cross with previous four categories. Agon is often the most rule-based and ilinx the least. In French there is no clear-cut distinction between "play" and "game", so Caillois might use ludus-paidia axis to add this distinction. Never-the-less, mimicry (closer to paidia) applies easily to Role Playing Games and ilinx (most paidia — least game-like) is present already in (rule-based) sports, and could be extended to computer games.
We can see mimicry, acting something out, in the musical interpretation itself. There are also music games that develop story or theme, sometimes bringing them closer to musical theatre (see more: Improvisational Theatre). It is also the area of music games where ilinx is clearly seen, when body movement is involved (body percussion being prime example). Ilinx factor is also indisputable when any larger, physically demanding instrument is played. Never-the-less these two factors are less frequent within music games than two others, alea and agon.
Praying to RNG gods
Aleatoricism is a modern composing technique that employs chance. "Alea" means dice, so is every aleatoric piece automatically a game piece? It depends, not only on exact preferred definitions of "music game" and "aleatoricism", but also on a process itself. In Caillois' interpretation alea (chance element in games) gains a ritual flavour as the point of gambling seems to be devoting oneself to some kind of higher power. This same helplessness is mocked in computer gaming by sayings like in the title (where RNG is "random number generator").
Needless to say, it's all about the stakes. You need to care about the result to have an engaging effect of letting off the control. In gambling the stakes are monetary and in computer games it's most often the considerable amount of time you invested in the game so far (maybe: aleatoric audition pieces would fit to raise the stakes?). In game design the focus is usually more on the subjective unpredictability than on technical randomness. Regardless if unpredictability comes from dice or opponent's choice, it always increases skill requirements, as you need to play out a situation unknown in advance to you. This is a bit paradoxical, because most often chance is considered to be opposite of skill, and Caillois suggests similarly.
Competition
Games of skill, agon are most often competitive and key feature of this type is 'evening the playing field' — giving fair chances to every player, known also as balance (the most basic type of it). Single player or cooperative games may belong to agon when the result of the game correlates to participants' skill. Although music games may not require a specific musical skill, usually players try to play as skillfully as they can. On the other hand, the natural state for music games might be between competition and cooperation (with co-optionality), this way tending more to irregular paidia than to rule-based ludus where agon resides.
Parting words
Despite having Huizinga as his basic source material, Caillois doesn't draw any direct connections between music and games, but the typologies and insights in Man, Play and Games find usage in game studies to this day.
