I recently joined the “KENNEY Game Jam” held recently. It was my first game jam. In this article, I would like to write about the game jam for indie game developers held on the itch.io website, including what I learned and felt while participating in the game jam.

What is a Game Jam?

A game jam is an event where participants develop a game in a short period of time, publish it, and evaluate each other. It is also called the hackathon of game development.

The itch.io site sells games, assets, and hosts a number of game jams worldwide. Some are held monthly, some are held as an annual event, and there are a variety of small and large game jams, and there is always some sort of game jam going on throughout the year. KENNEY Jam 2022 , which I attended, was also held at itch.io .

The participants in the game jam are mainly individual developers and small teams. Skill levels range from beginners to veterans. Although veterans are considered to have an advantage, many game jams have short submission periods, and in such cases, it is almost impossible to create a large-scale game, so it is difficult to make an overwhelming difference. I have the impression that there are a relatively large number of people, even beginners, who take up the challenge as one goal.

Of course, in order to participate in game jams held on itch.io, you need to create an account and log in, so if there is a game jam you want to participate in, be sure to create an account as soon as possible.

Why participate in game jams?


To someone unfamiliar with game jams (that would be me, until the other day), at first glance, this may appear to be a kind of competition with a broad appeal to the general public. Speaking of competitions, the best entries are ranked as winners or runners-up, and winners receive cash prizes and awards. Some game jams are like that, but most are not. Game jams are more of a festival. Participants play each other’s games and give each other feedback such as “your game idea is great” or “I was surprised by the novelty of your game system,” and get new inspiration and improve themselves as developers. This is the real thrill of a game jam.

And while it is a festival, it is also a great opportunity to show off your best work and let the world know about it and your skills and ideas. The best entries will naturally rank higher in the final evaluation results. This is a great honor, but it is not the only one. A high ranking in a well-known game jam will make the game more visible to many people and may even catch the attention of a major publisher. It can also give the developer a large fan base. In this way, the event can be a springboard to success as a game developer.

In reality, these benefits are only possible if the game is overwhelmingly excellent, but there is no need to be discouraged. Even if you do not create a game that will surprise everyone, there are other real values to participating in a game jam.

For one thing, you get to play a lot of other participants’ games. By playing and seriously evaluating other participants’ games, you can see other approaches that you did not have. This is a great learning experience.

Another is that you get to have your game evaluated by other participants. The ratings for the evaluation items are a good source of reflection, but the most rewarding feedback is to receive specific comments on your own game. It is not always praise, and it can be a little hurtful, but I consider feedback on areas for improvement to be the best growth material. It is a great opportunity to point out areas for improvement that you may not have noticed.

For example, the theme of KENNEY Jam 2022 was Growth, and I submitted Hungry Cyclops, a casual game in which a wizard feeds and raises his pet Cyclops, a one-eyed monster. The bigger the Cyclops got, the more the screen would shake when he walked. Although the game received high marks for its theme, several people pointed out that the screen shaking was too violent. This was a point that I myself was not very aware of. I realized the need to be very conscious of the user experience.

By the way, you can play Hungry Cyclops in your browser if you like. You can access it from the banner below.

Game Jam Flow

The flow of a game jam is roughly as follows

  1. eligibility, theme announcement date, rules for participation, etc. are announced in advance
  2. themes are announced
  3. submit your own game (most game jams last 2~3 days)
  4. evaluation of other people’s games (period of about 5 days to 1 week in most cases) 1. announcement of evaluation results
  5. announcement of evaluation results

Most of the rules and FAQs are published in advance, so it is a good idea to check them and decide if the game jam is one that you can participate in. In particular, check the rules carefully. Your usual game development procedure may be forbidden. The screenshot below shows the rules and FAQ of KENNEY Jam 2022.

The submission period after the theme is announced is often short, only a few days, and it is quite demanding to complete one game in that time. It is tempting to work on it without sleep in order to keep up with the other entries, but it is important to put your health first and make sure you eat and sleep well.

How should we perceive the theme?

A game jam comes with a theme. Developing games in accordance with the theme allows the games to be compact. In addition, game development with restrictions is surprisingly easier to generate better ideas.

I sometimes see people say, “If it’s too much trouble to adapt to the theme, just ignore the theme,” but I don’t think so. If we lose the evaluation axis of theme, the evaluation will be biased toward technical aspects such as graphics and game systems rather than ideas, which will favor only veteran developers.


The theme of the KENNEY Jam 2022 I attended was Growth. I expressed the theme by creating a game in which monsters are fed to make their bodies grow bigger. On the other hand, the same theme was expressed in different ways by other developers. For example, there were a thousand different interpretations, such as breeding plants, extending weapons, increasing the size of armies, making buildings taller, developing cities, making the growth of living creatures look like a picture book, and so on.

Furthermore, by giving these interpretations a game-like quality, the diversity of expression is further increased. For example, the game could be a 2D pixel art game to increase the number of mushrooms, or a 3D simulation game to develop a city by building along a grid.

Considering that the game will ultimately be evaluated by other developers, the main premise of the game to be submitted will be that the player can feel the theme. Be careful not to make too many original interpretations and make the thematic elements difficult to understand, as this will result in a loss of appreciation for the thematic elements. By creating games based on the concept of “making the theme easy to understand and the gameplay interesting,” the game will be more likely to be highly evaluated.

Personally, what impressed me about KENNEY Jam 2022 was the idea of a platformer game in which the size of the player character increases as it hits items. On the actual screen, the size of the player character remained the same, but the size of the background became smaller. I groaned in awe. It would be great if the theme is clear and the game can be expressed in a way that is unexpected and surprising.

Tips for completing games in a short period of time


If you have more than one week to submit your work, you will probably be able to create your game with a certain amount of time to spare. However, if there are only a few days between the announcement of the theme and the submission period, it will be a very difficult task to create a single game.

First of all, once the theme is announced, it may take half a day to a full day to come up with an idea of what kind of game to make and to establish the direction of the game. It will also take more than a day to actually code, prepare images, and develop the game. This makes it seem like an extremely difficult task to complete the game within the deadline.

However, there are a few tips for finishing the work within the deadline.

The first is to keep it simple throughout. Every detail must be thoroughly eliminated: UI design, character texture images and their animations, background music, sound, etc. There is no end to the amount of elaboration that can be done. What you should definitely be aware of is to thoroughly reduce the number of components in your game. The key is to try to make the game you submit as simple and compact as possible.

And second. When programming, copy and paste as much as possible from existing code that can be reused, and avoid writing programs from scratch by hand. For example, if I have an idea for a game, I start by considering if there is any code that I can use directly from games I have made before.

For example, in the case of “Hungry Cyclops,” the game I submitted for KENNEY Jam 2022, I used existing code for character movement, screen shaking, and path finding. As a result, we should have been able to reduce manual coding time and avoid unintended errors and the time it takes to deal with them.

Finally, the preparation of asset files for images, sounds, fonts, etc. There is probably little time to create these one by one. Be sure to consider purchasing them from an asset store (there are many free ones) or diverting them from something you have created in the past.

Incidentally, in the case of KENNEY Jam 2022, the rules required that 2D sprite textures and 3D models other than sounds and fonts be made from assets available on the KENNEY website, so preparation of the assets was very easy.

Tips for getting the other participants to evaluate your game

Once you have submitted your work on time, the next goal should be to receive as many evaluations as possible from the other participants. It is important to emphasize here that the goal is not to obtain an unreasonably high evaluation, but only to increase the number of evaluations. If the number of evaluations is low, the average of the evaluations may be skewed. People have different tastes in games, so if, for example, you happen to have only people who don’t like your game evaluate it, the evaluation results may deviate from the actual level of completion of the game. In short, we are saying that you should increase the number of times your game is evaluated and try to get appropriate evaluation results. Then, improvement activities after the evaluation will be more targeted.

By the way, especially in the case of a game jam with many participants, the work of evaluating others is also quite demanding. Many people may not be motivated by this task because their own evaluation does not change after evaluating others. So how can we get more evaluations?

Create a good cover image

When a participant’s game is listed on a game jam website, evaluators will first look at the thumbnail and instantly judge whether the game looks interesting or not. The cover image that serves as the thumbnail is extremely important as a first impression.

If the color tones are saturated and the image has a high contrast, it will be the first thumbnail that jumps to the eye. It is also effective to make the image focus on a character or other object that conveys the game’s content. If a screenshot of the actual game is used, it would be more appealing to enlarge only the important parts of the image and add titles to make the image more balanced, rather than using it as a cover image.

Next, platform selection is important. Generally, the rule seems to be to submit in one (or all) of four formats: Windows, macOS, Linux, and browser. However, occasionally there are game jams that specify only for browsers. And it is for browsers that it is easiest to start playing.

As long as the game jam is held on the Web, games for browsers, which can be played immediately on the site, are relatively easier to be evaluated because they do not require troublesome downloading and decompression of compressed files. Conversely, if a game is output for Windows or macOS, the number of times it is rated tends to be low because it requires downloading the file from the game jam’s website. This may be natural, considering the human tendency to avoid even the smallest of details, as they seem like a hassle to us. In the end, it would be best if we could prepare downloadable versions for other platforms in addition to the browser version.

Rate and comment on others’ work

A good way to get people to see your game would be to play someone else’s game first and comment on it, as itch.io’s game jams automatically display a link to the commenter’s game right below the comment.

Human nature usually dictates that since you went out of your way to play your game and leave a comment, you should play this person’s game as well. There is no need to leave unreasonably flattering comments, but it is a good idea to try to leave as many constructive and positive comments as possible. That alone should increase the chances that the developer of that game will evaluate your game.

Be careful when evaluating other people’s games


It is of course a prerequisite to always play the game before evaluation; if a game takes 30 seconds to a minute to play each time, playing it repeatedly 3 to 5 times should give you a general idea of how the game operates, how it works, and how interesting it is. If you play the latter half of the game while being aware of the evaluation items as much as possible, you will then be able to quickly determine your evaluation of each evaluation item.

In your comments, try to use positive expressions anyway. Please note that this is different from stating something that is not true.

For example, let’s say that a game you played was difficult to understand the operation procedure. In this case, a comment such as “The operation procedure was relatively easy to understand and I enjoyed playing the game from the first time” is not acceptable because it is not true. Also, the expression, “I felt reluctant to continue playing the game because the operation procedures were too difficult to understand,” is negative and should be avoided. On the other hand, “I would enjoy playing more comfortably if there was a function to highlight the next point to click!” is positive and conveys a fact, so it is acceptable.

If you are conscious of “making suggestions rather than denials,” you will be able to leave appropriate comments. Sycophancy is completely unnecessary, as it does not benefit the developer.

After the game jam is over

When the evaluation period for the game jam is over, the game jam is effectively over. If you simply leave the game jam at that point, you will gain less than half of what you could have gained from the game jam. First of all, check the evaluation results carefully and confirm the ranking of your work. Check the overall score, as well as the numerical values for each evaluation item and the comments from the other participants. From there, you should be able to see areas for improvement that you can apply to your next development project.

If you find any bugs in the submitted work, or if there are areas that can be immediately improved based on the evaluations and comments you have received, we will fix them and upload the game. This is in consideration of the people who will continue to play the game after the game jam is over. However, please note that if you do this during the evaluation period, only the files of games submitted earlier will be deleted and the modified versions will not be uploaded. It would be more polite and better if you add the revised version in the description.

Then, let’s play the games in the order in which they are ranked highest in the evaluation results. There must be a reason why the game was rated so highly. And be sure to take notes on the ideas and game systems that you think are good so that you can apply them to your own future work.


So, I wrote this article about game jams. If you are a novice game developer, I hope I have conveyed to you that game jams are worth participating in. In many cases, it is an opportunity to grow your development skills, and you should actively participate in game jams when they are convenient for you.

Let’s look back at some of the tips I have given you to lower the hurdles to participation. The English hurdle can be handled by using DeepL. In order to complete the game during the submission period, it is important to keep in mind that the game should be simple and compact anyway, while considering diversion of code and assets. After submission, in order to have your game evaluated, first prepare an optimal cover image. It is also important to be proactive and make sure to leave factual and positive comments once you play other people’s work.

I would also be willing to participate in other game jams if given the chance. If you have a chance to see my work at any of the game jams you attend, I would love to hear your feedback.