Crayon Physics Review

In one of my Interesting Stuff collections, I said I had another item that needed a whole post to itself. I was referring to the downloadable computer game Crayon Physics Deluxe (hereinafter referred to as “Crayon Physics”) which I heard about through Bioephemera.

Since then I’ve been meaning to post a review of the game, but just haven’t had the time. However, I’ve been working away at it behind the scenes, paragraph by paragraph, and here it is.

All comments herein apply to release #54 of Crayon Physics Deluxe.

Concept and Aesthetics

I love the concept of the game, wherein you draw pictures with crayon and whatever you draw comes to life. Crayon Physics takes you into a reality where you are half child and half god — where you can tie a rope to the sun and make a rock materialise on the other end — and what’s not to like about that blend of childlike innocence with godlike omnipotence? You use these powers to solve puzzles, and you can also create your own puzzles for other people to solve. (Here’s a link to one that I designed myself.)

Aesthetically, I find the game very pleasing. Games with realistic 3D graphics have been done to death, and different approaches are needed to stand out from the crowd. There is something delightful about using advanced digital technology to simulate something so childlike as crayon. If you enjoyed venturing into the child’s drawing in Hogfather — the book or the movie — then you’ll probably find a lot to like about Crayon Physics. I also think the background music is well suited to the theme and feel of the game.

The world within the game consists of a number of islands, each with a number of locations that constitute levels, and each of those with a particular challenge that the player must solve. Every level is a stand-alone drawing, and the best of them look just like something a young child would draw (although too many contain nothing but rectangles). The world between the levels — including the maps of the islands and the boat that takes the player from one island to another — are also drawn in the same childlike style.

As well as the crayon drawing, each level contains a ball and one or two stars. Stars are immobile, but most other things behave like physical objects. The player solves each level by making the ball pass over the star(s), and achieves this by drawing additional crayon objects with the mouse. These objects become “real” and obey the laws of physics as defined by the game, for example, you can draw a sort of pulley to lift the ball, or a hammer that swings like a pendulum to push it along. You can also make an object disappear after you’ve drawn it, which is very often useful.

How The World Behaves

You learn most of the game’s rules as you go along. In the early levels, the objects you learn to draw are all rigid, but later you’ll learn about floppy ropes and how to attach one object to another.

It’s hard to get a grip on the subtleties of the game’s physics. They are not documented in any detail, so you have to figure out how the world works by trial and error. This can sometimes be perplexing — it’s not always obvious why two objects sometimes collide and sometimes pass through each other, sometimes remain attached and sometimes fall apart. You will gradually get better at predicting how objects will behave, but unexpected things can happen even to a somewhat experienced player. A good way to improve your grasp of the game’s physics is to design a level of your own, which is a topic I will discuss later.

Certain techniques prove useful over and over again. One of the most versatile is the following strategy, which once mastered lets you solve many levels with very little thought:

  1. Draw a bubble around the ball. Elsewhere, attach a weight to a solid object so that the weight dangles over empty space. If necessary, draw some guides and attach them to solid objects to make sure the ball will go where you want it to.
  2. Draw a rope connecting the bubble to the weight.
  3. Undo the knots (called “pins”) that attach the weight to the object it is dangling from. The weight will fall under gravity, pulling the ball along, and if the guides are correctly positioned the ball will go right past the star.

Using this technique can get a bit repetitive, precisely because it solves so many levels for you. On the other hand, watching the ball being dragged along by a great big falling boulder can be rather satisfying (a bit like watching a really big avalanche from a safe distance … wheeee!). Another advantage over alternative techniques is that it doesn’t require much precision – simply draw everything more or less in the right place and the details will take care of themselves.

The need for precision can be a real pain with other methods of solving levels, for example drawing a hammer will often get you nowhere if the hammer is just a little too long or a little too short. This can completely ruin the fun — as soon as the game stops being a test of my ability to conceive a solution in my mind, and instead becomes a test of my skill at drawing something with exactly the right shape and size, it suddenly feels more like a chore than a game and I quickly lose interest. Besides, precision and crayon simply don’t belong together, and the fact that crayon is the medium of choice tells me that precision is not what it’s supposed to be about. So given a choice between a technique that gets somewhat repetitive because it usually works, and a technique that gets even more repetitive because you have to try it a hundred times before it works, I’ll go for the one that works every time.

My favourite levels tended to be the ones where the above technique is useful, but only as part of the solution, not as the whole solution. Two levels that I found particularly satisfying were “Ohoy!” and “Cave Story” (see if you agree).

You cannot save a game, as such. Your progress is automatically saved, and the next time you play you can either resume where you left off or start more or less from scratch. (I say “more or less” because there’s a strange caveat that I’ll come to later.) Starting a new game replaces your previous game, and you cannot store multiple games in progress.

Awesomeness and Elegance

I have completed the game (more than once) to the end of the seventh island. There is an eighth island, but I am completely unmotivated to try and reach it. In my opinion the eighth island is a waste of time, and the whole game is rather lacking in climax.

On the islands, you can click on a level you’ve already completed in order to either play it again or see information about your solutions. Three checkboxes — marked “Elegant”, “Old School”, and “Awesome” — tell you whether at least one of your solutions has met certain criteria. For example, one of the criteria for getting the “Elegant” checkbox ticked off is that you have to solve the level without drawing more than one object.

For each island except the first, there is a certain number of stars you must collect before you can visit it. At the end of the seventh island you will have eighty stars, but to visit the eighth island you need a hundred and twenty. What gives? The game tells you that you can earn an extra star by solving a level in three different ways, which is very badly put, but turns out to mean that you can earn it by getting all three checkpoints — Elegant, Old School, Awesome — ticked off. So to visit the final island, you need to get these checkpoints ticked off for half of the levels.

Earlier I said there’s a caveat to the statement that you can either resume your game or begin from scratch. It’s like this: when you begin from scratch, the game remembers which levels you’ve previously solved as Elegant, Old School and/or Awesome, and when you complete a level for which you (or someone sharing your computer) have met these criteria in the past, you get the extra star automatically. This is weird, especially if you imagine a friend playing with my copy of Crayon Physics and getting extra stars for no reason they can understand, just because I’ve earned them in the past. It might seem merciful to someone aspiring to that eighth island, but it would be completely unnecessary given a more conventional and sensible approach to the saving and re-loading of games (i.e. several saved games stored simultaneously, stored on request rather than automatically, and given names assigned by the player). Such conventions exist for a reason.

I think the checkbox thing is a really bad idea. What makes a solution officially “awesome” is not defined by the game, but by the fact that the player decides to mark it as such (although how to do this ought to be better documented). So anyone who gets the other two checkboxes ticked off and wants the bonus star is going to declare a solution to be awesome whether they mean it or not, as there is nothing to be gained by letting sincerity hold you back in the game. Even if the player is sincere, so what? If someone considers their solution to be awesome, it always says more about them than it does about the solution.

On my second run through the game I imposed the following criteria on all my solutions, but I wouldn’t claim any of them were awesome.

  • Nothing unexpected happens, i.e. nothing to make you think, “Hey! I didn’t think it would do THAT!“. For example, it occasionally happens that the ball accidentally flies straight into the star, causing you to win quite by accident
  • No taking advantage of the way objects respawn once play has started. For example, no using the same rocket twice. For similar reasons, if there are two stars to be collected in the level, collect both of them using just one ball.)

I like the “elegance” checkbox even less. In many levels, solutions that meet the “elegance” criteria are so difficult that I can’t even conceive how they might be possible. Moreover, as I mentioned earlier the game becomes boring if it depends too much on precision drawing: if you have to draw each object exactly the right shape and size. Sadly, so-called “elegant” solutions tend to be exactly like that, because when you’re only allowed to draw one object, it usually won’t work unless it’s drawn with almost pixel precision. For the record, I managed to fulfil the criteria for “elegant” and “old school” solutions in quite a few of the early levels, but stopped after a while because trying to meet these criteria honestly sucked all the fun out of the game.

Because I can’t get to the final island without accepting an excruciatingly boring challenge, I found the whole game rather anticlimactic.

Creating Your Own Levels

Crayon Physics comes with a facility to create your own levels, and to share them over the Internet. This is fun, but unfortunately the facility seems to have been tacked on to the game rather than being properly integrated, and there are issues that should have been fixed in beta testing. One glaring problem is a lack of documentation. The Crayon Physics website contains some pretty good online documentation for the level editor (and the information in it is absolutely vital if you wish to create a level of your own, for example it tells you how to draw “static” objects that stay still without being pinned) but there’s nothing in the game itself to let you know this information exists. Documentation is not something supplementary to a software product but an integral part of the product itself, and if you release software without sufficient documentation then you have released an incomplete product. I hope the information available online is included with the game in future releases.

Creating your own level is not only fun, but also a good way to increase your understanding of the game’s physics. For example, objects that have been drawn in several short strokes behave differently from objects drawn as enclosed shapes, and the level editor is a good tool for exploring such differences. The solution to my own level is pretty boring, really, but designing it was a good learning exercise for me.

Lines drawn with crayon are not continuous, but textured (like this: crayonsample), and particularly when drawn quickly are full of tiny little gaps. Objects can actually pass through these gaps and get jammed, a problem to which spiky shapes are particularly vulnerable. That’s why, in my fishing-themed level, I drew what are technically extra objects over the teeth and tail of the fish to reinforce their boundaries. This solution works for immovable objects but would not work so well for movable ones, and it would be good if the level editor had some sort of function to automatically increase the solidity of crayon lines.

Speaking of possible improvements to the level editor, I’d also like to see some way of continuing to draw a given line or shape after releasing the mouse button (very useful for large shapes). Also, the editor could give the user tighter control when deleting objects, so that they don’t accidentally delete the wrong one.

The way the game stores recently saved games in memory is extremely inefficient. Every time I saved my level during the process of creating it, the program slowed to a crawl, and I had to exit, restart and reload before continuing to work on it. Needless to say, this was really annoying.

Earlier I complained that the level editing facilities are not well integrated with the game, and cited lack of documentation as an example of this. Another example is that you cannot play a user-defined level as though it were a genuine level in the game, for example when you win a genuine level, a sound effect plays and you exit to the island, but on a user-defined level the star you have collected disappears silently and nothing much happens. The result is a reduced sense of satisfaction; some sort of acknowledgement of one’s success is important psychologically.

Having created your own level, you can share it online. But because of the way the preview images are generated, objects drawn in black will be invisible on the preview. That’s why you can’t see the fishing line in the level I designed — if I’d known this at the time I would have drawn it a different colour.

User-generated levels vary a lot in both quality and difficulty, and come with no guarantee that they are even possible to solve. You can rate the quality of other people’s levels, but it would be nice if the user community could rate them for difficulty as well (recording whether they are seemingly impossible, too easy, just right, or in between). It would also be nice if a level designer’s profile page (here’s mine) could contain some information about the individual designer and their philosophy of design. For example some of my comments in this review (e.g. my views on precision) might be valuable information for someone trying to determine whether to download a level I designed.

Some of the more difficult user-defined levels made me wish I could save the game in the middle of a level. None of the levels in the game itself are difficult enough for me to wish this.

Keep Out Of My Documents

By now you’ll have gathered that I think there’s a lot to like about Crayon Physics, but also have major reservations. I have one more reservation to discuss, and it’s a biggie.

I believe passionately that I have a right to decide how personal files on my computer should be organised, so it infuriates me when software products create their own folders within “My Documents”, without letting me choose a different location. Sadly, Crayon Physics is guilty of this crime. It creates a data folder in “My Documents” for storing levels you’ve created, records of your solutions, etc, and there’s nothing you can do except either put up with it or uninstall. This is a gross breach of etiquette, as it clutters up space that should be reserved for the user’s own files.

I appeal to software developers to choose one of the following alternatives:

  • Let the user decide where the data folder should go.


  • Put the data folder inside a folder that legitimately belongs to your software. So that the user can find it, put a shortcut to the data folder inside your software’s Start menu folder.


I enjoyed the demo version of Crayon Physics so much that I bought the complete game, and it has been a very long time since I last did that. This speaks for itself regarding my first impressions.

I do not regret my decision. Crayon Physics is worth more than a lot of other things you can buy for twenty American dollars, and it gave me days of genuine good fun, an outstanding aesthetic experience, one of the most inspired themes around, and the chance to exercise my own creativity in the level editor. That said, I deleted the game when I’d had enough of it, so it was a transient pleasure, and I suspect it will be the same for most people.

You have nothing to lose by trying out the free demo, and when you’re ready to decide about purchasing the full game, I hope that everything I’ve said will be helpful to you. Go through all the reservations I’ve mentioned, and balance them against everything that is good about the game (including the dirt cheap price). If, after all that, you decide to go ahead, it is very unlikely you’ll be disappointed.


4 Responses to “Crayon Physics Review”

  1. John Cowan Says:

    This reminds me of the classic childen’s book Harold and the Purple Crayon. And checking that link, it was indeed a direct inspiration.

  2. Flesh-eating Dragon Says:

    I’d not heard of that one, but there are other classic children’s stories with broadly similar themes.

    This is by far the most effort I’ve ever put into writing a blog post!

  3. Kevin Says:

    I have to agree with most of what you said, but I did find the challenge for ‘elegance’ and ‘old school’ extended the games fun.

    Bar the last, I managed to finish all levels the first night that I bought the game (very late night :)) so I was a little disapointed at how easy most of them were.

    Striving for the extra stars though was certainly a challenge, though on many I was nagged by the doubt that a solution was impossible. I now know that that is not the case and I was able to complete all ‘elegance’ and ‘old school’ challenges on all islands.

    Although you can access the last island after you receive 120 stars, It seems that you need to solve all other challenges (elegant, Old School and Awesome ) for 155 stars before you can receive the 2 stars for this one. (like most of this game, I’m a little vague on the rules.)

    The physics engine will leave you scratching your head at times.

    I did enjoy this game, but it left a lot wanting.

  4. Flesh-eating Dragon Says:

    A Youtube user named letao12 has uploaded elegant solutions to most levels, but even after watching some I have as much desire to emulate that feat as I have to teach myself professional-standard juggling (and for pretty much the same reason). Way, way too hard for me.

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