Portal Level Development

The purpose behind the creation of a level for Portal was to create a small puzzle based environment that would be challenging and used a variety of puzzle mechanics.  The thought process behind the level was to think of new and original ways to create puzzles in Portal using the resources and game mechanics available.  Care was taken however, to ensure that the puzzles would have an element of familiarity, in order that the player would not find the level too difficult due to overly-abstract concepts.  A delicate balance was therefore required to ensure that a player could feel excited and gain a sense of success after solving a particular puzzle, but to ensure the player did not become bored or frustrated if solving the puzzle became too difficult.

This player experience is obviously fairly subjective and relies on user testing to gain a solid idea of the complexity required for each puzzle.  The user testing was therefore started at the prototype stage of the project before the level was ‘beautified’ and made more aesthetically pleasing.

The initial design of the level started with a brainstorming session on the various different ways in which players generally solve puzzles in Portal.  To achieve this, a few sessions in the original, commercially available game were played to gain ideas.  This produced a list of Portal puzzle-solving techniques, such as the use of momentum to cross large distances, the use of the power-ball to activate objects and timed lifts and doors.

This list was then used to gather ideas on how these techniques could be re-used but possibly in a different, more interesting way.  This was achieved by drawing up quick layouts of a possible puzzle for each technique that seemed interesting.  So, for example, the first puzzle uses momentum to propel the player upwards towards a platform.  This particular puzzle was made a little more complex than the standard, early momentum puzzles in Portal however, by using two momentum elements to the puzzle that required a little physical dexterity and good timing to reach the goal.

Other ideas drawn up on paper were then used to extend the level using a variety of techniques.  When designing these puzzles it was important that they used at least one slightly different technique to solving them for each one.  This was to ensure that the player was kept constantly thinking and did not simply go through the motions of using the same method for the rest of the puzzles after solving the first one, as this could become boring and too easy for the player.

It was also important to interconnect some of the puzzles rather than have them as separate entities.  This helped to create the feeling that all the puzzles were part of a whole solution to the level which in turn gives the entire level a sense of purpose.  If the level does not have a single sense of purpose the player may feel that it is simply a collection of puzzles with no coherent thread or connection and the player may become less interested in any kind of final goal.

So, for example, near the end of the level, in order to send the power-ball through a portal, the player must open a hatch door near the top of a wall.  The hatch however, must be opened using a switch, but the switch is at the top of a lift.  The lift, however must first be activated using another switch on the other side of the room, but this switch can only be reached by placing two portals on a wall and using momentum to reach the platform the switch is located on.

After diagrams of various interconnecting puzzles were drawn up, the game prototype was started. This involved blocking out the basic rooms with some working puzzles and leaving the beautification of the level until after the user testing was completed in order to save development time.  During the prototype stage, attention was paid to the scale of the rooms and the distance between puzzle elements in order to faithfully recreate the desired puzzle.  This required constant user testing in order that the puzzle worked exactly as designed and that there could be no loopholes or shortcuts that would allow the player to cheat the puzzle.
The level was saved in various iterative states to allow the option of experimenting with different elements and to save time adding or removing those elements until the design was finalised.

Once the prototype was completed the level was ready for user testing, the level was now in a state where only the bare bones of the level were in place; its only purpose was to support the game mechanics.  The testing was done using a variety of users from different backgrounds to ensure a wide spectrum of experiences and therefore to be able tailor the level so that it could appeal to as a broad an audience as possible.

The test users included video game professionals, friends, family and colleagues who were a variety of different ages and came from a variety of different backgrounds.  This testing helped me gauge the difficulty of the level and adjust it accordingly.