Filament puts you in control of a spacesuit-clad hero who arrives at a deserted space station. The only person seemingly left on the space station is a sarcastic woman who has been locked in the control room. After an initial period of distrust, she quickly summons your character (whom she dubs Pluto) to save her by using his hacking skills to repair the many, many broken systems on the space station. Seems easy, right? Well, it may not be as easy as it sounds.

The basic idea behind Filament is that you "hack in" to objects around the environment, during which time you control a tiny adorable robot. The tiny robot has a glowing cord of light that trails along after it. Your goal is to loop the light around every white marker on the map without ever crossing over your own trail. The concept is simple enough on the surface and very easy to pick up and play.

At first, yes, it's simple. The goal is finding which path allows you to loop around the stage without actually touching anything. However, the game quickly starts throwing other features at you. Black pillars turn off your light cord if it touches it, so you need to avoid them. Some black pillars can be turned into white pillars by triggering certain white pillars around them as designated by arrows. To activate them, you need to thread a path around all of the black pillars while leaving enough space so you can activate the pillar once it changes colors.

Of course, that's only a taste. There are puzzles where the cord changes colors and must activate pillars of a certain color, ones that must be activated in a certain order, ones where you have to trigger them in a specific way to solve puzzles in the environment, and so on. The basic gameplay is straightforward, but it gives the game a lot of room to be fiendishly difficult.

Filament is fiendishly difficult. After the initial tutorial area, it throws you into the deep end of the pool and expects you to swim. Because the rules are so simple, there's plenty of room to punish the player within those simple rules. You'll have to weave elaborate and complex threads of light to find the correct solution to succeed. The game is also extremely good at throwing red herrings at you. Seemingly simple loops are probably the wrong path, and fairly often, the first pillar you can reach is one of the last ones that you should be activating.

Thankfully, the game is very relaxing. You can instantly rewind your last actions with a button press and restart a level with another button press. You can go back to try a different configuration if you can't figure out exactly what to do. You can also try going to different levels if a specific one is frustrating you, but you will need to eventually come back to where you left off. This is a game made to be played in short and simple bursts.

Filament is a puzzle game with one gameplay mechanic, and from our preview build, it's executed extremely well. It's simple to pick up and play, charming in motion, and complex enough to be a good workout for your brain without having to figure out what the developer was thinking. Puzzle fans should look forward to the full game when it comes out in March for PC and Mac.