The principles behind the Unknown Horizons game [1] are reminiscent of Ubisoft's popular free "Anno" strategy game series [2], and that's no coincidence, because Unknown Horizons is a clone of this popular series. The Anno games have been extremely popular for many years, but because the manufacturer has studiously ignored Linux, a few fans summarily started work on a clone in 2005. Now, thanks to dedicated developers, it is growing into a worthy competitor.

Tales of Yore

In the first versions of the clone, called "OpenAnno," during the game the player viewed a landscape from above and at an angle, as in the original isometric representation. Just two years later, however, the project ground to a halt. Then, in the spring of 2007, new developers took over the helm and made some drastic decisions. They tried to develop a variant with 3D graphics, in addition to the 2D version, but the developers soon realized they had underestimated the amount of time and effort involved. To simplify development as far as possible, they ditched the existing code from the 2D version and moved to the Flexible Isometric Free Engine, or FIFE for short [3]. FIFE facilitates the process of programming games with isometric graphics. However, shortly after this decision, lack of time again brought the project to a standstill.

All Good Things …

Fortunately, not much time passed before a couple of new enthusiasts adopted the project, and they have managed to sustain development to the present day. The clone project is headed by two project managers with separate responsibilities and it has adopted English as its main language. What was originally a purely German-language project has gained supporters from all over the world. Previously, one non-German speaker from India had helped translate the documentation and discussions with the aid of Google Translate.

The year 2009 saw another major change: To avoid a potential legal dispute with the owners of the "Anno" brand name, the project was renamed "Unknown Horizons." The name change at the same time emphasized that the makers did not want to create just a clone but a separate strategy game in its own right [4].

Unknown Horizons has since become one of the most famous open source strategy games for Linux. The project even took part in the Google Summer of Code 2011 and 2012. During these competitions, students particularly improved the artificial intelligence of the computerized opponents. According to the project homepage, 50 volunteers currently work on Unknown Horizons – a remarkably high number for a game developed solely during the developers' free time.

Game Play

During the actual game play, with a bit of cash in your pocket and a few willing emigrants on board, you beach your ship on a deserted island. Then, you quickly set up a small headquarters on the beach and embark on your conquest of the island. At first, food is provided by a fisher and hunter, for whom you need to set up accommodation in an appropriate place. The wood needed for more buildings is provided by a lumberjack. Paths help transport goods quickly to and from your headquarters. Settlers at first live in simple tents and buy their food at the marketplace (Figure 1).

Figure 1: Tents for hunters and lumberjacks nestle in the forest, the fishermen set up on the water, and settlers cluster around a marketplace.

Each building requires very specific environmental conditions: Whereas fishermen want to live near the water's edge close to the fish, the lumberjack needs to work in the densest forest you can find. Although you can plant trees, this will cost more money than felling the trees of the natural forests.

As prosperity increases, so do the needs of the settlers. At first, they only ask for food and a church; later, they want beer and cigars. All of these requirements must be met before the inhabitants move up in the social hierarchy, which at the same time unlocks other types of buildings (Figure 2). In most cases, you can't build these new structures from wood, which means setting up factories; for example, bricks are produced at the brickworks, which in turn need clay from a special pit.

Figure 2: As prosperity increases, the settlers independently extend their homes. At each stage, new companies, crops, and services become available.

If the island lacks some raw materials, you can buy them from traders for cash. Some enterprises don't just empty your cash register during the building phase, but also during operation; for example, the priest at the church asks for a steady wage (Figure 3). You can earn the money for all these expenses through taxes or by exporting the goods produced on the island.

Figure 3: Each building has its own intake area. Only the settlers residing in the green zone can reach this pavilion for prayer. Another church is required for settlers outside this zone.

As you slowly build a functional economic system, further settlements grow around your village. You can trade peacefully with the local inhabitants, forge alliances, or attack their villages and assimilate them into your community. However, before doing so, you will want to take the precaution of protecting your own production facilities with guard towers (Figure 4).

Figure 4: Manufacturing, import/export, and security are hallmarks of a successful economy.

Conclusions

Unknown Horizons is still under development, so you will come across display errors or unfinished graphics now and then. Although the developers have announced an exciting single-player campaign, it still doesn't exist. Currently, you can only generate a map and then set off to develop the island – either alone against the computer or on a network against other players. Settlers quickly reach level four, forcing you to set up all the buildings at quite an early stage. As the game progresses, you can't get an overview of the needs of the individual inhabitants – for now, you have to click your way painstakingly from house to house. So, much fine-tuning is still needed.

The development history has been turbulent because of lack of free time and frequent changes in developers and project managers – as is typical of many free game projects on this order of magnitude,. Unknown Horizon shows that good English language documentation is the prerequisite for attracting many supporters on the Internet and for taking part in the Google Summer of Code.

That said, the current developers are on the right track. As long as they don't give up again, Unknown Horizons could soon become a worthy competitor – at least for "Anno 1602."