Speaking of playtesters...
We needed a puzzle that would demonstrate the different effects that the fizzler has on the game. This map was consistently the one that most of our playtesters would get stuck on and we tried various things to make the puzzle easier to understand. Originally this room had 2 fizzlers in it and was divided up into three distinct areas. This proved to be too complicated and almost none of our playtesters could solve the puzzle. We removed the second fizzler and simplified the layout of the room quite a bit but most of our playtesters were still getting stuck on it. We identified the problem to be the space above the fizzler. Originally this space was completely open, but that didn’t effectively convey to the players that they needed to shoot a portal above the fizzler. We then tried putting glass with several holes in it above the fizzler. This was slightly more effective as players would know that the holes are there for a purpose and would try to solve the puzzle by shooting portals through the holes. The map was still not testing well though, as players could not figure out which side of the fizzler they needed to be on when they shot their portals. We then changed it to have only a single hole through the glass, moved down to the eye level of the player, so that shooting the portal from either side of the fizzler would be a valid solution. This change tested really well and we started seeing most of our playtesters make it through the level without getting stuck on it for a long time.
— Tejeev Kohli
