Gameplay design involves adjusting each mechanic's parameters. In the beginning we decide to create each mechanic thinking on using it in a certain way, but usually the thought effect isn't immediately the one we want. We need to realize an adjustment process, once we can observe in the engine how the different mechanics interact in practice. An example is the character's speed in a platforms game. We might need to increase or reduce the character's speed or his jump's height, as completing a level can take more time than the expected and bore us. Another example can be the aim. By modifying the precision's range, we can make it easier or harder to hit the bull's eye. Another example is the damage caused by a weapon in a fighting game. By modifying this attribute we make this weapon and its bearer more or less powerful and relevant for the video game. Adjusting the mechanics can take us to the extreme we realize that we need to create a new one or, on the other side, delete one. This happens when we see that the simple adjustment of the existent mechanics doesn't give us the desired effect in the experience. The gameplay design also involves giving each mechanic a specific importance regarding the others. During the different level mechanics will be mixed and intercalated, sharing the time game. Let's put the example of a jumping mechanic in a platform game. Well, in a level we can put a 25% of plain zones, in which there aren't holes or platforms, and the left 75% will be platforms in which the player has to jump. This is a kind of playability in which we give more importance to the jump than to the shifting or exploration. A platforms game can have this playability, as the jump has more importance than other mechanics present in the genre, such as exploring, beating enemies, solving puzzles and using objects. Also, apart from the total proportion, we must take into account how to mix and share it. Usually the different mechanics alternate, trying to create action and rest patterns that repeat during the level. If we have a 75% of jumping, maybe we want to spread it all over the level, using the 25% left in middle resting zones. Something similar would happen in shooting and combat games, in which shooting and hitting will be more important than exploring and solving puzzles. The gameplay's implementation is mostly a process which is applied in a circular way with the idea of improving the result in each application. First we implement a mechanic and then we evaluate its effects on the other mechanics that we have already implemented. Based on these effects, we change and adjust this mechanic's parameters. In example, if we see that an enemy is harder to beat than we expected, then we change its capacity of receiving damage to make it more vulnerable to our attacks. After each change, we evaluate it again, and this cyclically, until we get a satisfying result, or we end up discarding it as it doesn't fit as we expected. The evaluation part is very important. When we evaluate design and its implementation, we must be able to do it with a critical and active sight, knowing what we're looking for. We must try to foreseek where the fitting errors or problems can be in the mechanics. It is very recommendable that, apart from designers, people from other departments test the design, as sometimes being on the game as much as designers can be counter-productive, and a further look can bring clarity. To better use the evaluation we must note down all the elements we observe, to adjust them with more precision and agility. To improve the design implementation process it is recommendable to initially assume that everything will probably require an adjustment. We don't have to be obsessed with everything working and fitting at the first try. We must try different options, either the ones initially planned or the others that come out in each occasion. If necessary we can try taking it to the extreme simply to know what happens. We must also rectify if what we have previously thought of doesn't work, it is better to rectify and try to not force the situation, to make it work as we wanted it to. Finally, it is very useful to look for referents on how other games build their playability. To finish, we will talk on some gameplay styles which are usually used in media. These styles make reference to some key characteristics that differentiate them. We talk about a Casual gameplay when in a game we use few main mechanics, with a simplified control, little variety and little difficulty progression in short games, with a little history importance and focused to a non-expert audience. Arcade gameplay also involves an easy control, and few mechanics, but it shows more environments variety and more difficulty progression, with games with different length, where the story can have little or middle importance, and targeted to an audience that is already used to playing. Hardcore gameplay has a complex control, according to a wide range of controllable mechanics, in environments and settings with great variety and with a lot of difficulty progression. Games are usually long, with a relative importance of the story, as they usually look for multiplayer competitiveness, and targeted to an expert and exigent audience. Simulation gameplay offers a very complex control, with a lot of mechanics, with little difficulty progression, games tend to be long and without a lot of importance on the story, and they are targeted to an expert audience on the simulation's topic, as they look for a realist representation. Well, these tags are generalizations, therefore they aren't precise or exact, but they can be useful to quickly distinguish game types and associated experiences. In the next module we will use them to describe the different genres.