Is the videogame industry a creative industry like movies, where ideas can be bought and sold? Or does the central role of the game engine in blockbuster titles render innovation and invention meaningless against the practical constraints of game development?

The movie business is considered an archetypal creative industry. Ideas are circulated in the form of pitches or draft scripts which are optioned by studios as possible future projects. These studios are a centralised source of money, which is allocated to projects which are then staffed from the talent pool working in movies. No-one is irreplaceable in this system: star actors and actresses may be the biggest driver of box office receipts, but they can and are replaced. Directors have the leadership skills required to steer projects with hundreds of staff, but they too are replaceable.

It can be objected that the film industry achieves more commercially than it does artistically, but it can't be denied that the big studios keep money flowing to the talent pool working in film, thus keeping the industry alive. Creative, artistically valued films get made in the cracks between the studios because movie makers have a robust industry to fall back on. You can take more risks when you know there's somewhere safe to fall should things go wrong.

In many respects, the blockbuster videogame industry has modelled itself on the movie industry. Money is centralised in publishers who fulfil the same role as studios in bankrolling projects, for instance, and marketing practices show considerable similarity too. But in games, there is no mechanism for a pitch or 'script' to be floated independently of a developer. I often meet people from movies who have "a great idea for a game", but in almost all cases there is no conceivable way that idea can become a game. Why should this be?

It is not that games lack a suitable brief document equivalent to a script: concept documents are passed around all the time, and my company does quite a lot of work developing these concise descriptions of potential game projects. But publishers don't option concepts for games the way movie studios option scripts, and for very practical reasons. The process of converting a script to a film is well established and has no critical element that can't be shuffled around as the project develops. But the process of converting a game concept to a game is deeply and critically dependent on one particular asset, which has no equivalent in film: an engine.

Ian Bogost has drawn attention to the theoretical importance of the engine for game development. In many respects, the engine is the game - or rather, any given engine supports a wide array of games with fundamentally similar capabilities. The engine determines what a game can or cannot do, and the cost of developing the engine is so significant that for blockbuster games an engine must deliver at least three game titles to make it worth creating in the first place.

Engines are also big business: superstar programmers (i.e. uber-nerds) write the code that steps up the top end capabilities for graphics, physics etc. and these cutting edge engines are then licensed for big bucks. Companies like id Software only make games to showcase their engines, which are their real money makers. This radical monopoly on engine construction is a central feature of the games industry - there can be no game without geeks to make them, which means every blockbuster that gets made is almost guaranteed to be 'nerd friendly'.

There is no equivalent to the game engine in film production, and this is the primary reason movie studios can afford to trade in ideas (i.e. option scripts). Movie projects have no significant critical elements beyond budget. If you have money, you can make movies. But money alone isn't enough in blockbuster games: you can license an engine, but you still need geeks to make it do what you want, and if you have the requisite programming talent it might look better to have them write the engine in the first place, taking about five years by today's blockbuster standards e.g. Team Bondi and L.A. Noire (2011).

The game engine is never an off-the-shelf resource. Engines have their own inertia that makes it hard to change what they do and time consuming to maintain and upgrade them. This all requires a significant investment of programmer time to master - or tame. This is why blockbuster projects revolve around teams, and pricipally around programming teams and their leaders at the executive level of the business. Artists, game designers, audio, QA - like actors and directors in films - are expendable, exchangeable... But whomever keeps the engine running is almost irreplaceable, and whomever can lead the unleadable (since programmers are wilful beasts) becomes hot property in game development.

Engine inertia not only reflects the efforts to build and maintain program code of the relevant complexity to run a blockbuster videogame, it reflects the trend across all such engines. Game engines are locked into a competition to produce higher quality renders and more detailed fictional worlds. This state of affairs is made inevitable by the constant market pressure to sell more powerful equipment on the one hand, and the game programmer's addiction to technical excellence on the other. An obsession with perfecting simulation meshes with ever more powerful computer equipment to create an industry-wide engine inertia that drives towards more advanced graphics and other computational flourishes. The mass market for games doesn't care about this futile arms race, as the Wii and DS show, but gamers buy into it for sport, if nothing else.

Suppose we wanted to remodel the games industry so that it was possible to trade in ideas, like the film industry - how could this be achieved? Arguably all that would be required would be an industry-wide standard engine, something that could be taught as the basic tool for making games. With this common footing, a shared methodology (equivalent to that used in film-making) would reduce the emphasis on technology and allow for more fertile creativity. Engine inertia would still have an effect, but it would occur on a  slower scale - compare the many decades 35 mm film was standard, to the sudden obsolescence of engines in games.

However, this fantasy is misguided. Hollywood trades in ideas because movies are mass market, and there's an appetite for novelty. But even then, the ideas it trades in are rather conservatively construed. A standardised games industry would still be making simulated fictional worlds, and these are not mass market. They appeal to gamers, not all-comers. Since gamers actively enjoy the high degree of fidelity, complexity and capacities that result from escalating engine inertia, the current situation serves them as much as the programmers (hardly surprising, given the crossover in tastes).

Thus it seems that games can never be a creative industry in the same way as films. We will never be open to inventive concepts brought in by a lone creative individual, as can happen in movies (at least on paper!) and those games that get made will tend to lean heavily towards the play needs of the nerds who program them. Engine inertia blocks the possibility of creative invention by placing a necessary requirement for programming as the essential and irreplaceable component of any blockbuster game title. While this is the case, innovation in games is heavily constrained, and this situation is unlikely to change any time soon.

Videogames are a creative medium, but they are only barely a creative industry. Engine inertia blocks this possibility by making code resources the critical element in any blockbuster game project. As a result there is no trickle-down from the funding of big games to the support of small, artistically interesting projects. Until this can happen, videogames are almost exempt from cultural esteem, being little more than expensive geek toys. I'd love to see this change, but at the moment the economic conditions are poisonous to risk. While code is more important than ideas, creativity necessarily suffers, and games are doomed to fall short of their potential.