Puzzles are a tricky thing to design, especially in games with unique physics mechanics. They need to have defined end goals without giving away those end goals too easily. Make a puzzle too hard and it’s frustrating, but make it too easy and it’s no fun. It’s the solving itself which people enjoy, but if you don’t give them a direction to work towards, you risk players walking in circles and becoming frustrated, feeling like they aren’t making any progress. Maintaining forward momentum is key. You can actually see some of these same level design elements in both the Portal series and in the newer Superliminal game, to varying degrees of success, particularly in the designs of the smaller puzzles in the larger story setting.
The main thing I noticed between the two games (three, if you count the original Portal game and it’s sequel separately) is the use of doorways and exits to mark different sections of puzzles. For Portal, you have the test chamber doorways, painting an end goal to every test chamber which is itself the puzzle, while Superliminal showcases a very similar effect with their wavy, semi-transparent doorways. They also both feature item-limiting factors to prevent players from bringing unwanted puzzle objects in between puzzles via the emancipation grill in the former and the unnamed wavy effect in the later. It’s no surprise that the Portal series and Superliminal keep getting compared in this way, given the overlap of these game mechanics. A doorway is a goal to work towards, and having clear markers between sections of puzzle solving helps players to demarcate different puzzles from one another. Both games even have elevator transitions between levels, although that may be more of a resource saving effort to hide loading times.
Superliminal struggles in its late-game levels, where exits and puzzles become much more difficult to solve. The challenge with using optical illusions as a core gameplay mechanic is that in hiding your solutions from players, you can frustrate them by giving them little-to-nothing to work from. While the early levels mimic Portal with their clear goals and exits, many of the later levels require maze-like navigation, often with maps which don’t make real world sense. A looping hallway is a really cool effect to program, but if your player can’t figure out how to escape the loop, it just becomes frustrating.
From my experience playing Superliminal, the final levels of the game were the most frustrating, because it felt like the door mechanic the game had worked with up to that point became a little muddled and lost. In particular, the level 8 section has you enter a square room with no apparent exits, just rows of filing cabinets stacked high with papers and a couple standing lights. Even our guiding exit sign is missing, replaced with a similar but distinctly different ‘Not an Exit’ sign. To escape the room, you have to walk through a heavily-cast shadow on the wall, which is actually a hole in the wall. The lighting and staging of the area make it unremarkable to the other shadows cast in the room, except for its size as big enough for us to pass through.
I very much enjoyed playing both games, but while the levels in Portal 2 are equally as challenging near the end of the game, I never felt as lost for a direction to work towards as I did in some of the Superliminal levels. I want to replay some of those early levels, as I think they’re much more solidly workshopped and finished from a design standpoint, but the late game levels of Superliminal gave me an actual headache to solve. But I would happily dedicate an entire day (or 2 or 3) to replaying Portal and Portal 2 all the way through again. Or maybe I just prefer GLaDOS to the nameless AI lady of Superliminal. Who’s to say…