Modern 3D games under Linux used to be challenging even before the first round of play, with tricky settings in Wine or installation of its commercial version, Cedega. Crude hacks in the settings files required that gamers have a high level of experience with Linux. Numerous strange bugs kept appearing in the games, but the game providers didn't care because they occurred only on Linux, a strange niche operating system, instead of the officially supported Windows platform.

The year 2010 saw changes in this unpleasant state of affairs when some game developers started turning to Java as an operating-system-agnostic development language. Mojang's Minecraft enjoyed outstanding success as an independent title, running under Windows and Linux almost equally well – some even said it ran better under Linux. Around the same time, the game provider Valve decided to develop hardware in addition to its Steam platform [1]. When deciding on an operating system for their Steam Box, a gaming console, Valve chose Debian Linux. One of the many reasons for this choice was probably that highly technical 3D games native to Linux already existed at the time. The ego shooter Sauerbraten has been demonstrating since 2003 that a gamer can manage to roam smoothly around 3D landscapes, fight, and die under Linux.

Additionally, the Valve managing director and co-founder Gabe Newell was deeply disappointed with Microsoft Windows 8. He described it as a catastrophe for the PC as an open system for gamers and issued urgent recommendations for a change to Linux [2]. At the end of 2015, the search function for Steam [3] reported that more than 1,500 games on the Steam platform officially ran under Linux (Figure 1). At the same time, development of native Linux games forged ahead, and some of these games are also available with a free license. I tried out two Steam offerings under Linux – Cities: Skyliness [4] and ARK: Survival Evolved [5]. I also tried 0 A.D. [6], which is a native real-time strategy game with a free license. The "Test Equipment" box details the hardware used in the tests.

Full Steam Ahead with Steam

If you want to play Steam games, you have to register on the Steam website and then download and install the Steam client for Linux. Currently the program forces users of Ubuntu 16.04 to retrofit. (See the info box titled "Steam on Ubuntu 16.04.") The entire registration procedure comprises just a few steps and asks only for an email address, password, and username. Ideally, you can specify a telephone number that can be used in the event of problems to verify the account, although this is not needed most of the time. If you forget your password, Steam will send the data necessary for a reset to the registered email address, just as other providers do.

LD_PRELOAD='/usr/$LIB/libstdc++.so.6' DISPLAY=:0 steam

The Steam client installs on the computer across the entire system via a Debian package. All of the games acquired with Steam are located in the home directory of each user. Steam installs them in the hidden ~/.steam directory. All of the game data, such as configuration files, game scores, and mods, are found in one folder. It is possible to start some of the games without a Steam client directly from this storage location. However, this only works for those few titles that have abandoned restrictions on the right to copy/ (See the info box titled "Steam and DRM.")

To purchase games sold for a fee you need a credit card or a PayPal account. Other payment alternatives include direct withdrawals from your bank account or prepaid cards that can be purchased in stores. There are also many store locations where the games, like products from Google Play and iTunes, can be purchased. The Steam client requires a login when called for the first time. Thereafter, the program starts without asking for a password.

Steam works well across platforms – which you'll notice in the fluid displays – even though it was built for Linux-based hardware. However, the program is not presented as a piece of software that is deeply embedded in the Linux desktop. For instance, it ignores system language settings and always loads in English. Steam activates an icon in the system tray that hides a menu you can access with a right-click. It contains an option for Settings where you can easily change languages. This right-click menu is also the only place to go to end Steam. Closing the main window only ends its own module, but the back end continues to run.

The Steam shop is convenient and free of clutter. The search function comes with a list that includes simple icons and short descriptions. One click in the list displays the page for the game together with a demo and useful information about the system requirements. Two clicks with the mouse suffice to buy a game (Figure 2). The game then appears in the profile, but only in the list of purchased items.

Figure 2: Steam gives detailed information about the fact that ARK is still under development. The "SteamPlay" log indicates official Linux support.

To download the game, click on the Install button, and it is installed in your home directory. If the procedure is cancelled, Steam will first check the size of available memory. If the partition fails with the home directory, Steam offers to install the game on a different data storage device. It can take a little while to complete installation. For example, ARK: Survival Evolved comprises 15GB of data.

ARK – Paleo Survival Deluxe

This huge download is a promise of things to come. ARK is in its early access beta phase. Studio Wildcard has designed the game with fantastic attention to detail. Even the landscape looks remarkably genuine, and the 200 plus animal species that populate the landscape have been created with the standard of artistry found in epic movies like Jurassic Park. Their artificial intelligence has also been programmed with a love of detail that makes for an incredibly convincing experience of interactions that occur among the animals themselves and between the animals and the gamer (Figure 3).

Figure 3: Wilderness and wild animals make ARK a thrilling experience. An update released on the day before the publication deadline added considerably more dramatic weather attributes.

The only thing that jerks the gamer back into reality is the motion animation, which is sometimes bizarre. For instance, a Parasaurolophus stuck halfway under a boulder can go into a continuous loop of strange contortions. The mixture of survival, adventures, and sandboxes is nonetheless appealing. Those who proceed strategically and learn which animals can be hunted and which animals are better avoided advance quickly. Most of the animals can be tamed with a little experience. When one of the living fossils gets stunned and then fed, you get a non-player animal that transports, loads, and defends you against other monsters and takes you on a ride through the wilderness.

I observed a limited number of technical problems during 700 plus hours of play. Occasionally the game falters, but it always returns to very normal and smooth operation within a few minutes. Occasionally the animation does not work properly, but this problem is limited to particular areas of the playing field on The Island. Online servers let you experience adventures collaboratively. The play there often proceeds at a brisk pace. In addition to standard play modes PvP (player versus player) and PvE (player versus elements), a primitive mode only permits the use of stone tools. (See the "Multiplayer" info box.)

In PvP mode, human gamers play against one another either as individuals or in so called ARK "tribes." The idea is to see who can dominate the playing field. In PvE mode, gamers try to protect themselves against the elements either by working together or collaboratively. The elements include monsters and other dangers. Cooperation is permitted but gamers are supposed to avoid animosities.

ARK ran smoothly on the PC with GTX 750Ti graphics. When the settings are moderate, it has sophisticated textures and anti-aliasing. The game was just barely playable on the IdeaPad laptop, and then only with graphics settings that make a carefully designed game look like an experiment from the 1990s (Figure 5).

Figure 5: The textures appear flat and the horizon is small on a laptop with the GT 620 GPU; however, the low-resolution settings make it possible to play the game on slower systems.

Therefore, if you are on the go and want to see tame dinos eat, you can make do with a mobile system. However, the real fun comes with more power. The various modes and extensions also need a system with more vigor because they include multiple super monsters and entire maps. Since the middle of May, an especially detailed map,"The Center," has been available as an official ARK add-on.

Cities: Skylines – The Mayor's Office

Cities: Skylines is a complex city-building game that has demanding hardware requirements. It is somewhat more complicated to play but less adventuresome than ARK. Like the classic game with a similar name, the goal is to establish a city in a landscape of choice and build it out beginning with an exit on an Interstate. The inhabitants pay taxes that can be used to construct all kinds of power stations, streets, police stations, and other infrastructure. This then attracts more inhabitants to the city who generate more revenue, thus making it possible for the city to grow in size.

In addition to the game itself, the equipment includes editors for scenarios and gameplay elements. The game creator, Colossal Order, offers Cities: Skylines via the publisher Paradox Interactive, who also runs the community portal (Figure 6).

Figure 6: From the game's Home screen, you set up an account on the Paradox Interactive portal. On the right, you can see the long list of Steam expansions available for the game.

The many different possibilities are so well structured that even a first grader can have fun constructing a city. However, children who want to play should be able to read, because some of the ingenuity of the game depends on being able to comprehend detailed explanations provided in the tool panels. A player also needs to pay attention to the chat messages sent by inhabitants of the city to the player, their mayor. These communications report successes, but they also point to problems that are easy to overlook in the complex general overview (Figure 7).

Figure 7: A municipal finance department is one of the many administrative gameplay elements found in Cities: Skyliness.

Cities: Skylines did not run well at all on a laptop. Just the start time itself lasted as long as a quarter of an hour. With a desktop PC, on the other hand, the game booted in testing without any problems after four or five minutes – much like ARK. The camera view affords an especially impressive perspective, in which the player can observe the city with photorealistic graphics.

A good city planner can begin to govern a city with 10,000 inhabitants after just 10 to 15 hours of play time, bearing in mind that fascinating construction and infrastructure elements continue to increase in number. Of course, all of this comes with interesting problems, such as environmental damage, over-indebtedness, and similar issues, thus challenging the intellectual capabilities of the game players.

Cities can be expanded with numerous mods available from the Steam workshop. In addition to many details, such as snow and rain, you have terrible catastrophes that include a volcanic eruption.

0 A.D. – Classical Antiquity in Modern Times

Unlike the two Steam titles, the open source game 0 A.D., developed by Wildfire Games, at first looks like it lacks complexity. However, first appearances can be deceiving. This is not a project put together by a hobbyist during off hours. In fact, 0 A.D. offers the most important of the properties usually found in professionally developed games: The concept is well thought out, and it has been carefully implemented. Nothing about 0 A.D. is purely experimental. Everything that has been implemented works perfectly and makes a thoroughly professional impression.

On their mailing list, the developers discuss things like the appearance of the sandals worn by Roman Legionaires some 2,050 years, and whether the shooting range of the Iberian slingers has been accurately portrayed when they are presented in the game as a deadly danger for advancing Persian warriors. Even the historical names given to the champion non-playable characters (NPCs) in the game are unknown to most because Asterix , a Franco-Belgian comic that ran from 1959 to 2010 [12], is the sole source for much of the knowledge about this time period. The attention to detail is fun for fans of classical history, and contributes significantly to the game's rich atmosphere.

The basic themes of the game are economy and conflict. Ethnic groups like Persians, Celtic tribes, Greeks, and Indians construct houses, fields, and forts in unspoiled environments according to legendary and historical records. They then have to struggle against other groups controlled either by online players or from the remarkably more powerful artificial intelligence (AI; Figure 8). Testing did not reveal any technical problems, and 0 A.D. was the only game tested that worked well and delivered well-rendered graphics on a laptop with a 600 generation Nvidia card. The game did slow down noticeably with scenarios that had more than three game partitions as soon as the number of NPCs was greater than 500.

0 A.D. is definitely less spectacular and less complex than the two Steam candidates, but I had no complaints in terms of how it handled. The current version comes with a conquest mode that makes the battles between the groups more interesting and adds excitement to the clashes. The website contains directions for building mods and scenarios and instructions for character design in the Blender graphics program (Figure 9).

Figure 9: Atlas, the scenario editor in 0 A.D., lets you create custom playing fields for 0 A.D. and edit the available maps.

Conclusion

Nothing stands in your way of playing a challenging video game on Linux. None of the games tested here showed any defects attributable to the operating system. However, each of the candidates requires current, proprietary drivers. Two of the games, ARK and 0 A.D., can function to a large extent with free Nouveau drivers. For ARK, these drivers do cause serious restrictions, though. 0 A.D. has far fewer restrictions. All of the games tested are worth the purchase price, because it really does pay to spend time with them.