[Note: I received a free copy of this game in exchange for a fair, unbiased review.]

There’s something immensely satisfying about building a contraption and then setting it into motion. Marble runs, Rube Goldberg devices, clockwork toys, chain reactions… they all involve a meticulous step-by-step creation process that builds anticipation as you go.

And then finally, you get to pull the string, throw the lever, drop the marble… and enjoy the clicky-clacky fruits of your labor.

But I don’t think I’ve ever encountered a game that makes it both as challenging AND as effortless as Gravitrax does.

Allow me to explain.

Gravitrax takes the traditional marble run formula — gravity x (tracks + ramps) = good times — and improves it in every way.

The hexagon matting provides a stable base that not only makes it easy to follow the instructions included for all sorts of designs, but makes the entire design perfectly steady. Every piece fits snugly into the hexagons, so there’s none of the wobbly uncertainty that can ruin a flawless marble run.

Factor in ALL of the pieces provided in the Starter-Set XXL — columns of two different thickness to raise pieces, plates to create entire new levels to build speed, curves and connectors galore, plus specialty pieces to add new tricks and challenges — and you have an amazing launchpad for creating your kinetic designs.

So much thought has been put into all of the pieces included. There’s a triple launcher so you can race multiple marbles along different paths OR set up different chain reactions all at once to dazzle the eye.

There’s even a magnetic accelerator that can launch a ball uphill to add further distance to your track!

The instruction books are another standout part of the package. Like a LEGO manual, they’re completely wordless, and yet, everything is crystal clear. The first book introduces all the pieces and how to use them, while the second (much thicker!) handbook offers all sorts of designs to try out, starting from simple to complicated and challenging ones. There are six difficulty ratings in all.

And the instructions lend themselves to puzzly minds. They show you the finished product first, so if you want to try to puzzle out how to build it yourself, you’re welcome to. If not, just keep reading, and you can follow the step-by-step instructions, complete with piece listings so you know exactly what you need for each step.

I’ve been a sucker for kinetic puzzles and games like this my whole life, and I can only imagine the crazy contraptions and high-speed runs younger me would have spent hours testing and assembling with a kit like this.

So when I say it’s both effortless and challenging, I mean it. This incredibly well-designed set can be picked up by a child immediately, and yet, there’s enough adaptability and opportunity here for new designs, more innovative builds, and limit-pushing attempts at speed and complexity.

I mean, it’s nearly 2 AM as I write this, because I spent two hours trying out a new idea I had instead of writing this review.

I’m not sure I can pay the Gravitrax Starter-Set XXL a higher compliment than that.

[The Gravitrax line of building toys is for any number of players, ages 8 and up, and it’s available from Ravensburger and participating websites (in numerous models and styles). The Gravitrax Starter-Set XXL starts at $129.99.]