OTC is a real-time strategy game (RTS) in which the human or computer-controlled players each run a company on Mars. There they mine raw materials and process them in factories to meet the needs of the Mars colony. The real goal is to achieve the highest possible profits with which the competing companies can be taken over. From the perspective of economic education, an attractive feature of this approach is that it does not involve the use of military means as is usual in this genre. Instead, the conflict is primarily fought out via markets and the skilful exploitation of the mechanisms of pricing via supply and demand.

Although OTC does have economic learning potential due to its economic focus, learning its game mechanisms is quite complex. In this sense, it is likely to be suitable for teaching purposes only in exceptional cases and is more suitable for semi- and informal learning situations. As OTC is only available in English and due to the degree of complexity, the game is particularly suitable for young people and adults. The replay value is very high due to the numerous game modes and the multiplayer option.

OTC is available from Steam for 20 euros (reduced for 6 euros). There are also some DLCs available, but these are dispensable. For the multiplayer mode, only one license is required, which allows up to nine additional people to play for free.

The game is available for Windows and MacOS and Linux and has quite moderate hardware requirements, so it should be applicable on many school computers. An internet connection is only required for multiplayer games.

The game begins with exploring the map and determining a location for your own station. The location should be as close as possible to the required raw materials with a high yield. Of particular importance at the beginning are raw materials that are needed for the further development of the base, i.e. aluminium and, depending on the base type, carbon or iron as the basis for steel production. If, on the other hand, only very few resource fields are available from a raw material, an alternative is to try to occupy all of these fields. This gives the player a monopoly which he can use to increase prices by selling little or nothing at first.

Since the number of available land pieces (claims) is very limited, but increases with the level of the base station, it should be increased to levels 2 and 3 as soon as possible. The necessary raw materials aluminium, steel or carbon should usually be produced by himself, whereas the production of glass is usually not suitable at first and should rather be bought on the market.

An important principle in OTC is that adjacent factories of the same type show increased efficiency, which can be explained economically by synergy effects and economies of scale. Therefore, normally at least two and possibly three units of the same type should be built next to each other. In principle, it is advisable to concentrate on those resources that promise high profits. Since land is very scarce, it may be worthwhile to demolish existing factories and build more profitable factories on the land.

As the game progresses, special buildings can be constructed to allow research into new technologies and more efficient mining methods. There are also buildings for additional income and to manipulate market prices. With so-called 'black market activities' you can, among other things, protect your own buildings from attacks by competitors and initiate measures to damage your fellow players.

With all measures, the financial strength of the own company has to be taken into account, so that the indebtedness remains within a manageable range, since with increasing debts the creditworthiness decreases and the interest rate increases.

The game ends as soon as one player has acquired the shares of all competitors, but this requires considerable financial resources.

1 Areas of competence

Decision and rationality: In OTC, challenging decisions have to be made on a permanent basis and have to be questioned or revised on the basis of current developments. This applies, for example, to the use of the available land, to alternative uses of the available money (e.g. repayment of loans, other investments, purchase of opponents' shares, purchase and sale of resources, activities on the black market) or to the use of resources. In some game variants without a break option, considerable time pressure is added as an aggravating element.

Relationship and interaction: Basically, OTC is a confrontational game in which the player competes with real or computer-controlled opponents for victory. Nevertheless, the players interact intensively with each other, either directly through sabotage actions or mainly indirectly through market processes. For example, players who have a monopoly over a commodity can only sell it very cautiously on the market and thus increase its price. In the context of multiplayer games, it is also possible to design cooperations based on the division of labour and increasing efficiency. This allows players to focus on certain resources and to allocate them to their partner, which can give a team an advantage over other player groups.

Order and system: The central playing mechanism of OTC is market processes in which prices fluctuate in line with supply and demand (with high volatility). The ability to affect prices indirectly via one's own supply and demand behaviour promotes an understanding of market processes. It also highlights some of the functions of free prices, as they signal the scarcity of certain resources and can lead to adjustment behaviour by market actors, for example when unprofitable productions are stopped or replaced by more profitable investments. Also, mechanisms of competition and consequences of monopolies can be more deeply penetrated by actively dealing with OTC.

2. categories

• Division of labour/specialisation/efficiency: Players need numerous resources to develop their base. However, the aim should not be to produce all of them yourself. Rather, it is advisable to produce a smaller number of products and to produce them in higher quantities, since several production facilities of the same type located next to each other are associated with significant efficiency bonuses. This reflects the principles of specialisation and economies of scale in the game. In addition, investments in patents and more efficient production technologies can be used more selectively. However, this efficiency strategy is also associated with certain risks (see below).
• Need: The basis of the game is the needs of the colony, for whose satisfaction the player bases exist in the first place. Especially goods that satisfy existential needs (e.g. water, food, oxygen) are in regular demand.
• Networking: Most of the activities of all players influence the other players indirectly via market mechanisms or changed resource prices. For example, if someone builds a new power plant, this will tend to lead to falling energy prices due to the higher supply.
• Scarcity: Dealing with scarcity is a central challenge of OTC. Depending on the playing card, certain resources are available in large quantities or (almost) not at all. In the latter case, one strategy could be to secure the scarce resources and develop a monopoly. In addition to mineable resource deposits, money and processed materials are also in short supply. Especially in the further course of the game, there is a greater challenge in the limited land, which may have to be met by demolishing and converting existing factories.
• Cost-benefit thinking: The question of an appropriate cost-benefit ratio must be considered in numerous issues, for example:
  • Which materials should be produced?
  • Should one factory be demolished in favour of another?
  • Up to what amount is it worthwhile to bid at an auction?
  • Which patents, productivity gains, market manipulation and black market activities are worthwhile?
• Risk/uncertainty: In principle, for reasons of efficiency, it makes sense to focus on comparatively few resources (see above). However, if other players focus on similar resources, a comparatively high supply and low market prices can be expected. Furthermore, the dependency on the (hardly predictable) market increases, as several products may have to be bought at high prices. Other aspects of uncertainty arise in research activities for patents: If another player researches a technology first, they are no longer available to the others and the research time that may already have been invested was useless. There are also risks regarding attacks by other players on your own city, against which you can protect yourself to a certain extent with protection expenses. Occasionally, random events influence the game, such as an earth or Mars quake, as a result of which the prices of all resources increase noticeably.
• Growth: It is crucial for the success of the game to allow your settlement to grow quickly, especially in the early and middle phases of the game, as more resources can be mined and processed.
• Conflicting goals: In OTC, there are numerous conflicting goals that need to be managed, such as
  • Growth/investments vs. debt reduction vs. buying own/foreign shares;
  • high efficiency by focusing on few products vs. market independence through diversification;
  • long-term high efficiency through research spending vs. short-term availability of financial resources
  • stable prices of a self-produced resource through restrained sales vs. increased direct revenues

3 Contents
OTC's learning potential for economic content lies primarily in market processes including pricing through supply and demand, but also aspects such as (unfair) competition and monopolies as well as opportunities for market manipulation.

Furthermore, challenges of debt are depicted, since the interest rate rises noticeably with increasing debt or decreasing creditworthiness.

OTC also addresses economies of scale through specialisation, efficiency gains through research and the consequences of technological developments on the demand for various products.

4 Technical errors
Misconceptions are hardly likely to be encouraged by playing OTC. In this context, only two aspects should be considered:

- The volatility of prices is very high, which makes sense from a game-mechanical point of view, but is rarely found in reality at this extreme.
- Sabotage, which is an important gambling element, is illegal in real economic life, but most players should be aware of this anyway

OTC has significant economic learning potential. However, the familiarisation period is comparatively long, so that it can hardly be recommended for use in normal lessons. However, OTC is certainly suitable for semiformal learning settings such as study groups.

To get started, it is a good idea to play the tutorials, although the 4th tutorial does not necessarily have to be played to the end, as it is very difficult. Since the tutorials explain the game mechanics quite well, only little (if any) support by a teacher is needed to learn the game. However, it is a good idea to play the tutorials in small groups and to activate the pause mode again and again, so that the students can advise and support each other. At the latest after the completion of a tutorial, an exchange of experiences about gained knowledge and possible problems in the overall plenum should take place.

A large part of the economic learning gain can already be achieved with the tutorials. If sufficient time is available and the participants are interested, free games against computer opponents or multiplayer games against other group members can still be played, which can be especially motivating. In any case, a final reflection should take place at the end of the game phase, in which, for example, the following questions should be discussed

• What is important to pay attention to in OTC? What are promising strategies? Which mistakes should be avoided?
• What have you learned by dealing with OTC?
• Which economic aspects of the game do you consider (un)realistic?

• Comprehensive English-language Wiki with numerous information including tips and guides