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Creating Puzzle Adventure Mail Tail as a Solo Developer

Robin Heisterkamp talked about the challenges of making games independently, discussed the gameplay of Mail Tail, and shared how its colorful world was created.


Hi, my name is Robin Heisterkamp and I've been enamored with the idea of making games since I was very young. My interest in game development started after my older brother introduced me to titles like Gothic and Spellforce. I immediately knew I didn't just want to play games, I wanted to make them.

So, I started playing around with 3D software like Wings 3D and Blender when I still was in elementary school. I played around with several game engines like Unreal Engine, Unity, and CryEngine.

After school, I went on to study Computer Science but I never really found the thought of working for a software company that appealing. I always had a very strong creative drive and not having an outlet for it would honestly drive me crazy. My parents were very happy that I still finished my degree but I was honestly already on the outlook for something else to do.

Luckily, I met one of the founders of OverToon Studios as he was giving some design courses at my university. Thanks to my 3D skills, I was able to join the studio as an artist and contribute to many animated music videos that we worked on over the next two years. I also picked up some concept art and illustration skills while I worked there and this eventually helped me to get a job at the games company I'm working for right now – Cipsoft.

I'm now helping them build new online games while working on my personal game projects on the side.

Solo Development

Creating games independently means you are in complete creative control over your art, your code, and the music. I love showing people things that excite me and making a game means I get to do this with every aspect of the project. I think making a piece of art and sharing my visions with others is one of the most rewarding experiences I had in my life.

The main difficulty at the moment is just having too little time. I'm working my day job at Cipsoft while developing Mail Tail, and this means I have to put every bit of free time into making this game.

On top of that, I've just started to be more active on social media to get more eyes on my work. The response I'm getting for the game is quite encouraging but it's also taking away precious development time.

I have a lot of custom tools that increase development speed and I'm also able to repurpose a ton of code from previous projects. But it's still an uphill battle.


I think the answer to balancing the creative and business aspects largely lies in finding the right game idea. You need to find one that you are passionate about, that is within your ability to execute, and on top of that, it should also be appealing to a larger audience. I spent a good amount of time looking at other games, analyzing what could be a good visual style and gameplay hook for my own project.

It's actually quite easy to convince someone of your game idea when you yourself are genuinely excited and I feel like this is one of the biggest advantages that indie devs have over AAA companies when it comes to marketing. Just be honest about your game and let your passion shine through when talking about it.


I would say that I'm generally a pretty motivated person and this already helps a lot. I'm mostly excited to make games when I wake up in the morning and this is probably more of a character trait than anything else.

But there are actually days when I feel like the project isn't going in the right direction and this can definitely lead to a lot of frustration and even questioning the entire game development endeavor as a whole.

One tip I have for any game dev out there is to surround yourself with amazing people that you can talk to, maybe even whine a bit about how difficult all of this is at times. Get yourself some emotional support because game development is hard! And having someone around who is familiar with the project and your situation is also super valuable to overcome creative blocks and get another angle on your work.

Advice for Beginners

If you go into game development, don't expect a massive hit right away. You'll probably have to work for a few years before you get your first commercial success. So don't do it for money but because it's awesome!

When it comes to indie games specifically, I'd say good ideas beat execution. A lot of indie success is built on creative, novel gameplay ideas or art styles. Just look at games like Crypt of the Necrodancer or Choo-Choo Charles, to name a few examples. Your game doesn't need the highest level of graphical fidelity but it needs a reason why people should care about it. If you're able to show off what's special about your game in a 3-5 seconds GIF, you're good to go.

And don't neglect the social media aspect of game development. You want to get as much feedback as possible to get a feeling for what people are responding to in your work. On top of that, it's always a good idea to build an army of followers that support you and your projects.

Mail Tail

When I started with game development, I was mostly inspired by games like Gothic, Spellforce, and Dark Souls. I always wanted to create a complex RPG that was just like these games but with my own touch. It may sound pretty crazy, but I spent about a decade trying to improve my skills to a point where I can somehow achieve this impossible goal.

At the end of 2020, I was very burned out because I still hadn't released anything despite putting in so much work. I decided to take a break and look at some indie games to get inspiration and potentially come up with a new game idea.

The one game that had the greatest impact on me was A Short Hike by Adam Robinson-Yu. I love the game's art style, the music, and the traversal mechanics. It blew my mind that this game had been created by a single developer in such a short time. After watching Adam's GDC talk on how he made the game, I decided that it was time to get back to work. I finally wanted to finish a project and release it.

The setting of A Short Hike was a good starting point for me and I quickly began brainstorming and adding my own ideas into the mix. I had just played The First Tree by David Wehle, which sparked the idea to have a fox as the protagonist and the theme of mail delivery came to mind because I had just watched Violet Evergarden.

I want to create a game that is focused on exploration and environmental puzzle-solving, but I hope I can still include some influences from my earlier inspiration like the vertical level design that is seen in Dark Souls or the intricate dialogs of Gothic. My former game project had a dark fantasy setting and while I certainly have a soft spot for these kinds of games, switching to the more light-hearted world of Mail Tail felt so envigorating and refreshing that my motivation was restored in an instant.

Art Style

When I started working on Mail Tail, I created a big mood board with screenshots of different games that serve as inspiration. I wanted to create a world that has a very hand-crafted, painterly feel to it but I also tried to find ways to reduce the workload in some ways. Increasing the camera distance to the player may have been the most useful trick in that regard. When the camera is farther away, you don't have to create as much detail and flaws become much less apparent.

A lot of the inspiration for the art comes from games like Zelda: Breath of The Wild, League of Legends, and Ori and the Blind Forest.

I spend a good amount of time creating concept art and coming up with unique designs before translating them into 3D. This is an extra step that is skipped by many indie devs because it's so time intensive, but I feel it really helps with the art direction and look development.

Game Engine

I use Unreal Engine. It has an extremely robust set of tools and free source code access, and I love the combination of node-based scripting and C++ programming. The development process with Unreal has been incredibly smooth so far and I just get a lot fewer technical hiccups than with other engines that I've worked with. I feel like Unreal Engine is a phenomenal engine for 3D games, especially because of its performant culling algorithms and overall great rendering capabilities. I would maybe consider a more lightweight framework if I was making a 2D game though.

On the 3D modeling side, I mainly use Blender, and the textures are largely created in Photoshop. I used to work with Maya for animation and rigging but I've been trying to switch to Blender lately since I prefer having everything in one software. Blender doesn't offer as many tools as Maya when it comes to animation, but I managed to mitigate most of its shortcomings with custom python scripts and plugins.


The goal for me is to make the puzzles as unintrusive as possible. It should just feel like you're interacting with different systems in the game world and figuring things out on your own. I actually really enjoy games like Limbo or Inside, which have a more straightforward approach to puzzle design. But I think this would be a bit immersion-breaking in the context of my game's world.

A good example of the puzzles in Mail Tail is the quest where you deliver a letter to a frog in a flying house. You first have to find an axe and chop some wood. Then you can use the wood to light a fireplace inside the bakery. And you can then use the updraft from the smoke coming out of the chimney to get to your destination. (Well, this is a spoiler but I've been frequently showing this in Videos, so I think this is now officially my example puzzle.)

Traversing the Island

The most prominent tool is likely the Postal Delivery Umbrella. You can use it to glide through the air and get to places that are difficult to reach. There are various other items like the Hermes boots that let you double-jump or the swimfins that allow you to swim longer distances.

I don't have a set approach when coming up with these items. It's mostly either an environmental obstacle that sparks an idea or I see something in another game that gets me thinking.

I like to design my world in a way where you need to find specific items to overcome natural barriers like cliffs or long stretches of water. Witnessing the moment when a player finds a new item and realizes it can be used to overcome an obstacle is super rewarding for me.

The World

There is a common problem that a lot of game developers run into fairly early when developing a game with a more open-level structure. The usual approach is to use a height map-based terrain that is created in the engine and then "decorated" with smaller props to add detail. This approach is by no means bad, but it comes with a set of challenges or inconveniences.

First of all, creating cool cliffs or caves is fairly difficult because a standard height map-based terrain is not able to store information about overhangs. Working on a height map terrain can also be quite rigid and moving bigger parts of your level to make room for more extra content is often just not possible. Lastly, going back and forth between your modeling software and the engine can be a pretty time-consuming process. Especially when creating a bigger mesh that is supposed to enhance the terrain in any way.

My solution to this problem was to do the entire world creation inside Blender. I use it to build the base mesh of the terrain and I also do all the prop placement in the software. I then use a custom tool to export all of the object coordinates to Unreal where the scene is reconstructed to look exactly like the version I'm working on inside Blender. I was super happy when I used this workflow for the first time because I realized that it solved almost all of the issues I was facing with height map terrain. Placing props inside Blender turned out to be extremely fast, and it allows me to make big changes to the world quickly. With this setup, I'm now able to create very complex structures and vertical-level layouts. Creating the world is still a difficult task though.

I've probably reworked every part of the world a few times and I often discard areas completely when I don't feel they live up to the rest of the game. Overall, creating the world is a very iterative process and I'm just glad I found an approach that allows me to go back and forth until I'm happy with the result.


I'm currently trying to collect as many wishlists as possible before the game gets released on Steam. I hope to make a big splash on launch day this way and get noticed by Steam's algorithm. If your game performs well enough in the first few hours after release, you have a chance to get featured on Steam's front page. This usually results in a huge boost in sales and it can be the deciding factor in your game's commercial success. To achieve this, I'm trying to redirect all my social media traffic to the steam page. On top of that, I'll reach out to game journalists, provide review copies and contact steamers to play the game when it comes out. As previously mentioned, a big factor here is my limited time. Sadly, every hour I spent on marketing can not be used to make the game better and this is probably the biggest obstacle I'm facing at the moment.

Tips to Attract Players

First of all, I've never released a game before, so I can only give some tips that are based on my experiences on social media as well as some tips I learned from others.

  • Your game's visuals matter a lot because a book is actually judged by its cover in this case. You don't need to look like an AAA game but make sure your art style is cohesive and your marketing art grabs the viewer's attention.
  • Make sure your shop site is localized (I'll have to do this soon) and upload a trailer and pictures that get your players hooked.
  • You can use GIFs on Steam to better illustrate your gameplay in the description section.
  • Make sure you communicate clearly what you're getting when buying the game. You don't want a bunch of negative reviews because of misleading information.
  • You should have at least 10,000 wishlists before you release the game if you want a chance to be featured on Steam's front page.


My plan for 2023 is to finish the game or at least get it to a really good state. I also want to focus on growing on social media and building a following for my next projects. I recently uploaded my first proper YouTube video and I hope I can follow up with a new devlog soon. The game still needs a lot of content before I can call it done and I hope I'll be able to complete it soon and move on to the next project.

Robin Heisterkamp, Artist & Game Developer

Interview conducted by Ana Kessler

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Comments 1

  • Anonymous user

    The game already looks increadible and the advice and experience from the creator is very eye opening. Can't wait for the game to be finished!


    Anonymous user

    ·a year ago·

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