Portal Singleplayer Puzzle
Producing a single player level in Portal was an exercise in singleplayer, puzzle-based design. As usual it began with some blocking of the basic form I had envisioned.

Blocking out the Portal level
The design was worked on further with added elements to the puzzles. The level was tested regularly by a variety of players and adjustments were made according to the results of the playtesting.

Constructing more of the Portal level
The level required a variety of scripted events and sequences to be added in order to function the way I had planned. Also, given that it is a puzzle game, every possible eventuality that would enable players to exploit and essentially ‘cheat’ at the puzzle had to be thought through. Fortunately the player testing helped with this a lot.

The second, and trickier, room.
The level was split in to two main sections; the image above shows the final room with an elaborate and tricky puzzle to solve.

Portal Level – First chamber
The image above is the first major room the player enters and the site of the first puzzle. This puzzle is meant as a warm up for the second room as it contains similar puzzle elements.

Another angle of the second room.

View from the top of the second room.