When Gel Meets Wave

Gallery 1
Gallery 1

Gallery 1
Gallery 1


Level Summary

A single-player test chamber in Portal 2. The level is broken into three main puzzles with the repulsion gel and the wave (aka. Excursion funnel) as core mechanics. This level requires the player to understand different usages of the repulsion gel to solve the sub-challenges.

The intermediate version of the level was featured by Steam Workshop and got over 250 ratings after one week.

Steam Feature Page
Steam Feature Page

MOD Page
MOD Page

Steam Feature Page
Steam Feature Page


Development Info

  • Game: Portal 2

  • Genre: Puzzle

  • Mode: Single Player

  • Team Size: 1 Developer

  • Engine: Portal 2 Editor

  • Development Time: 20 hours


  • Puzzle Design

  • Level Building

  • Lighting


Walkthrough Video


Map 1.png
Map 2.png

Design Goals

Build a good ramping up process to teach the key skills

  • Creating a Gel Wave


Room 1: Send the initially existing gel wave to the right position. 2 steps.


Room 2: Create a gel wave and send it to the right position. 3 steps.

Room 3: Need more accurate execution when making a gel wave. 4 steps

  • Disorienting Turrets without Touching Them

Similar sub-puzzles in all three rooms: Get the cube from turrets’ guard.
More threatening turrets appear in the later rooms.
The bouncing turrets actually bring a hilarious scene that entertains the players a lot

  • Making an Angled Plate with a Bouncing Surface

Room 2: Press the button and the player witnesses the bouncing moment.
Room 3: Create a bouncing surface for an angled plate to get a cube.


The Player Always Knows the Goal

  • The player can always see the exit clearly before he enters the puzzle rooms.

  • The puzzle elements are clear and keep consistency: a press button, a cube generator, and a weighed button.


The Player Won’t be Punished for Experimenting

  • A deep pit with portal-able surfaces to get out.

  • Glass is provided to keep the player away from turrets when observing

  • The cleansing gel can be found in every room.

  • Mind the position of the deadly goo.


What Went Well

  • The level is built based on a clear and solid core mechanic.

  • Both the main objective and the sub-objectives are clear and easy to get.

  • Get lots of tests during the Whitebox and Gameplay Complete phrases.

  • Most testers feel this level makes them feel smart and excited.

What Went Wrong

  • The attempt of making an integrated room like a real Portal 2 level failed.

  • Many cheating methods in the early milestones.

What Went Well

  • Playtesting is extremely important.

  • The importance of the warm-up puzzle.

  • Don’t make the player feel overwhelmed.