Games are among the least well preserved media of the past half century, and the reasons are legal and institutional rather than technical.
The scale of the problem
Studies surveying commercial availability of games released before a given date have found that the overwhelming majority are not available for purchase in any form.
Which compares unfavourably with film and music, where catalogue availability is far higher.
The consequence is that studying or experiencing the medium's history generally requires either original hardware or unauthorised copies.
Why it is harder than film
A game is software requiring an execution environment, not a recording that can be transferred to a new format.
Which means preserving the data is insufficient — the hardware, operating system and peripherals must also be preserved or emulated.
Online components add a further layer, since a game requiring a server is unplayable once that server stops.
Emulation
The main practical approach.
Reimplementing the behaviour of original hardware in software, allowing original code to run on modern machines.
Accuracy varies enormously — an emulator that runs most games is far easier than one that reproduces hardware behaviour exactly, and some games depend on obscure hardware quirks.
The legal position is generally that emulators themselves are lawful, having been established in litigation, while distributing copyrighted game data is not.
The institutional position
Libraries and archives in several countries hold game collections and face legal constraints on providing access.
Copyright exceptions for preservation exist in many jurisdictions and typically permit copying for archival purposes while restricting remote access.
Which means an archive may lawfully hold a game and require a researcher to travel to a reading room to see it, even where remote access would be technically trivial.
Campaigns for broader exceptions have been fought repeatedly, with industry bodies opposing on the grounds that remote access would substitute for commercial sales.
Abandoned and orphan works
Where the rights holder cannot be identified or no longer exists.
Which is common given studio closures, acquisitions and the informality of early development.
Nobody can grant permission, and nobody is likely to enforce, which leaves the work in a legal limbo that discourages institutional preservation.
Orphan works schemes exist in some jurisdictions and are generally too cumbersome for large collections.
Source material
Beyond the shipped product, development materials — source code, design documents, asset files — are what allow genuine study.
Much of it has been lost, since studios did not archive systematically and storage media from the period degrades.
Recovery efforts have found material on old drives, tapes and in personal collections, and several significant recoveries have come from former developers rather than from companies.
Live service and the newer problem
Games designed around servers are structurally unpreservable under current practice.
When the servers stop, nothing remains, regardless of how well the client is archived.
Which is a category of work that will simply not exist historically unless practices change.
Releasing server binaries at end of life, as some studios have done, is the available solution and is not standard.
What individuals can do
Keeping original media and hardware in good condition.
Supporting institutional archives and the legal reform they advocate.
And documenting — recordings, screenshots, written accounts — which preserves something of works that cannot be preserved directly.
Physical media degradation
Optical discs suffer from layer separation and dye degradation over decades.
Cartridges are more durable and contain batteries in some cases, which fail and erase saved data, and battery replacement is a common restoration task.
Magnetic media degrades fastest, which means material from the earliest period is most at risk and least likely to have been copied.
Digital rights management
Copy protection systems tie games to authentication servers, hardware or accounts.
Which means a game may become unplayable when a validation service ends, regardless of whether the media survives.
Some publishers have released patches removing protection when discontinuing services, which is the responsible practice and is not consistent.
Documentation
Manuals, packaging, promotional material and press coverage all form part of the historical record.
Which digital distribution has largely eliminated, meaning contemporary games leave a thinner documentary trail than those from decades ago.
Community archives collecting patch notes, storefront descriptions and update histories are doing genuinely valuable work that nobody else is.
Legal deposit
Several countries have legal deposit schemes requiring published works to be lodged with a national library.
Coverage of software and games varies, and where it exists it has produced substantial national collections.
Which is arguably the most effective preservation mechanism available, since it operates automatically rather than depending on someone deciding a work is worth keeping.
Format migration
Archives copy data from degrading media to current storage, then migrate again as formats age.
Which is ongoing work rather than a one-off task, and it requires sustained institutional funding of a kind that is chronically difficult to obtain for a medium still regarded as ephemeral.