Principia is a toolset as much as a game - one that enables you to build your own games and contraptions from a set of virtual materials, motors, and special components.
But here's the thing. I find the vast majority of 'build-your-own-fun' games interminably dull.
Fortunately, the developer has included enough options to leave even people like me moderately satisfied - if not completely won over.
It's a wind-up
It's tough to say with a game this wide open and free-wheeling precisely what the point is, but for much of the time it's to guide a little wind-up robot through a 2.5D environment to an exit point.
Yes, developer Bithack (which made the similarly themed Apparatus) has built a game out of its own toolset.
Click on the 'Play' option in the main menu and you'll be given two variations: Main Puzzles and Adventure Introduction. The former is a simple selection of physics puzzles that show off the game's strengths, while the latter is an adventure-shooter that shows off its weaknesses.
But the main point to note here is that the developer has included plenty of content for those who like the idea of building virtual worlds more than the reality.
Deconstructing a riddle
Let's start with the Main Puzzles mode. Here you get a series of almost-finished obstacle runs, and it's up to you to fill in the blanks using a handful of leftover components.
These levels may appear somewhat clunky, and even amateurish, but they serve to show off the potential of the game's construction engine brilliantly.
There are stages that require you to build bridges out of wooden beams. Others require you to set off elaborate Rube Goldberg contraptions that incorporate rolling balls and even explosions.
With many of these puzzles, there's no single perfect solution - and if there is, you can often subvert it and solve the puzzle in a different way.
One stage involves an elaborate motor, trampoline, and ball bearing setup. I bypassed all of that completely by attaching a plank of wood to the motor and using it to move the motor out of the robot's way. It felt equal-parts naughty and clever, and that's why it was such fun to solve.
Adventures in DIY
As mentioned, the adventure section isn't so hot. In fact, I'd go so far as to say it's terrible.
Here the game's basic set of multi-purpose tools, aimed at getting even idiots like me into level creation, is exposed for its lack of sophistication. Why would I want to play a clunky action-platformer with shoddy movement and shooting controls, just because it's been built using a simple level editor?
I wouldn't. And nor will you.
That leaves Principia's vast creative element, which, for those who are sufficiently committed and creative, will provide hours upon hours of entertainment.
More than just a toy
You can create your levels or toys from the exact same tools we've discussed from the developer-made stages. These building blocks are generally easy to manipulate, if not completely seamless or smooth, requiring mainly time and patience to master.
Even here, the uncommitted gamer can feel a part of the community. Head over to the Discover section from the main menu, and you'll be greeted by the uploaded efforts of the Principia community.
As with the Adventure section, few of these are actually fun to play for more than a minute or two, but there's the extra spark of interest that comes from knowing that a regular player just like you has constructed these levels.
There's an undeniable fascination in playing a game of pinball on a bodged-together set of virtual planks, springs, and motors.
And that's Principia's whole appeal, really. The fun is in the chaotic, amateurish ingenuity of it all. It's about building your own rules and smashing those laid down by others - whether that's the developer or a fellow enthusiast.