Gamasutra: Simon Carless’s Blog-Case Study: Core Defense for Successful Solo Development

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[The GameDiscoverCo game discovery newsletter is normally written by ‘how people find your game’ expert & GameDiscoverCo founder Simon Carless, and is a regular look at how people discover and buy video games in the 2020s.

We’re delighted to feature this guest post by Mario Kaiser on his ‘tower defense with a tiny bit of deckbuilding’ Steam title Core Defense. Some of you gunning for multi-millions may turn up your noses at Mario’s $50k (so far!) But his strategic moves scale up, which is why this is a quality learning experience for all.]

A few months ago, I released Core Defense on Steam and earned $ 20,186 in the first week. There’s nothing crazy, but it’s good enough for solo indie developers. Especially if you can expect to see two to five times more revenue in the first week of the first year, according to Simon Carles, who isn’t fully recommended in the newsletter.

Currently, I’m about 2.5 times my first week’s revenue and haven’t sold it on Steam yet. This will make you more than double the profit on your wish list at launch. And since the game is coming soon to Android and iOS, overall, Core Defense has so far called it a somewhat successful indie game.

This post-mortem analysis (which includes many of the r / gamedev AMAs) shares lessons learned and gives my view on why CoreDefense has had modest success.

Of course, this post contains a lot of recommendations, but if you’re also interested in prohibitions, check out the post-mortem analysis of the first failed game Coregrounds.


I’m a minimalist, so I like simple things. But that didn’t prevent my last game from becoming a complex monster.

This time, we created a variety of strategically versatile games that are simple yet highly reproducible. I think that simplicity is one of the reasons for the success of Core Defense. There is no tutorial and no tutorial is needed. Its simple and dopamine-rushing core loop: receive rewards, update builds, survive the next wave and repeat.

Incorporating simplicity makes it easy to tell what the game is and why people should care about it, which helps sell the game. Players can jump in quickly and get to the fun faster (yes, your game needs it too).

Oh, did you mention that simple games are not only fast to build and easy to maintain, but also much more fun and rewarding to work with?


My first game was to bleed the player from the beginning. And that wasn’t just the complexity of the game I mentioned above. Aside from the terrible user experience, the game was full of bugs and technical issues. All of these could be avoided altogether.

When we talk about games and selling things, we always talk about ways to reach more, but I personally think that’s the wrong way to go. I think we have a huge market available anyway and we need to worry more about losing people than reaching out to more people. By releasing your game on Steam, you can get your game in front of thousands of people no matter what. Therefore, you need to lose as little as possible.

Quality isn’t everything, but without quality everything is nothing. At Core Defense, quality is our top priority and we strive to eliminate friction as much as possible.

Everything from game design and user interface to Steam capsule images is very clear and engaging, designed to be as enjoyable as possible. Among the many positive reviews, some called it “one of the best tower defense games” on the market. 1 2 3 4 5 6

Community-led development

For Core Defense, we chose a community-driven development approach. Within two months of finishing the concept, I created an alpha version and created a Discord server for people to play with. I kickstarted the server by warning the previous game community (which eventually spins off Core Defense) and game outlets like AlphaBetaGamer.

Since then, Discord servers have been constantly growing and have become a valuable resource for game development. Much of the content in today’s games is based on player ideas and feedback. With countless bugs and issues reported, the community is an endless source of both motivation and inspiration.

One of the reasons this worked so well was that I was actively involved with the community, reading everything the community posted in full and commenting on most of it. The same applies to discussions in the Steam community. There are virtually no posts there without feedback from me. So this is a fair amount of work, but no minute is wasted.

Sophisticated store page

Your store page is everything: you can have the best game ever, but no one knows if no one intends to go through the store page. Overall, I spent at least a week creating and tweaking the Steam store page. There isn’t much content, so the description fits within the visible range without scrolling.

In the last few months, the game has sold about as many copies as it won the wishlist. I think this is a strong store page and good pricing metric.

I chose the $ 9.99 price range, primarily for minimalist graphics that obfuscate production value. I’ve heard all sorts of feedback about this, but in most cases the price could have been fair or higher. But the price was perfect and I think it sold well.

Release strategy

You may not know that visibility will improve in the first month of its release on Steam. After learning this in a difficult way in the previous game, this time I wanted to get the most out of that boost by releasing a sophisticated product on Steam and converting that traffic as much as possible.

After reading about Martin Neurkar’s launch strategy for Nowhere Prophet, which had an early access phase via before it was released on Steam as a finished game, it turned out to be perfect.

After a short public alpha, we released a beta version of Core Defense on in mid-January 2020, six months before it was released on Steam. I think it was very important to have the Steam store page ready for the release. We have announced a free Steam key to all game owners, including the Steam Wishlist widget on the store page.

In the end, Core Defense sold only about 150 copies there, but that was enough to continue community-led development and reach the level of sophistication needed to nail the Steam release.


More than half of the game’s sales come from non-English speaking countries. This may not be entirely due to the fact that the game is localized to almost 12 languages, but I’m sure it helped.

Crowdsourced localization through, which was still in beta at the time. It was already good at that time, and it just gets better and better.

We were able to add a different translation to the game with each update, thanks to the community, just by adding an action phrase to the game’s home screen. Store pages that I have continuously translated via What I could do better here was to collect translators through the Discord server, which helped me because there was no way to ask most translators to update.

Standalone demo

When I came across Mike Rose Pre-release demo thread on Steam I decided to give it a try right away and created a standalone pre-release demo on Steam. It turned out to be a success. The demo gave us about 3000 wishlists of the game, among other many other benefits outlined in another blog post. The demo was the most effective thing I did in terms of the time and money I spent on marketing.

There is definitely a demo in my next game as well. The only question is whether it will be standalone. On-page demos are less work-intensive and less expensive, but standalone demos benefit from increased visibility on Steam. This means that for just $ 100, you can make a big difference in the game by paying additional app credits. You can also participate in the Steam Festival with the on-page demo. This is great. However, you also need to actually run the live stream for better visibility (unfortunately, we didn’t do it).


Apart from the demos, influencer outreach was by far the most effective marketing tool for core defense.

  • I used dodistribute and Keymailer to distribute the keys

  • We did an Indie boost campaign to release a beta on and spent about $ 200 on sponsored influencer videos with good results.

  • Before the launch of Steam, I used Woovit to send the key to influencers. It was picked up by a few small things, but there wasn’t a big reach here.

  • Two weeks before launch, I created a Keymailer ad for $ 100. This gave us about 80 major requests and some videos, but again we don’t get much.

  • Before and after the release of Steam, I finally wrote a cold call email to many larger influencers that looked like a perfect genre match. One of them actually covered the game!

Apart from working with influencers, I did the following:

  • Post regularly on Twitter (#screenshotsaturday!)

  • Posted about the game to various related subreddits

  • I wrote a press release, posted it on, and sent it to my (self-collected) press list.

  • Made some important giveaways on different platforms

  • Posted about games on IndieDB and various indie game forums

  • I shared my data and knowledge on my blog and platforms like reddit


It feels like an outsider creating games using JavaScript in an era when Unity seems to dominate the indie space. But I love languages ​​and the ecosystem. It also makes it easy to create cross-platform games with a single codebase, without any licensing costs.

The game engine is custom, but I rely heavily on Vue.js and Pixi.js, Electron, Capacitor, and some small helper plugins such as Steam integration and mobile advertising.

In fact, I like the setup so much that I plan to make a boilerplate in the future. It contains a beautiful release script that runs tests, builds the game and uploads it to all platforms.

[SIMON’S NOTE: Thanks for the insight, Mario! Very much agree that having a ‘killer’ core game loop, working closely with the player community to build up interest & get pre-release feedback, and localizing widely are some of the biggest factors in Core Defense’s solo dev success & positive player reception so far.

That’s it for this week on the GameDiscoverCo newsletter – unless you’re a GameDiscoverCo Plus subscriber! They’ll be getting an extra missive about the hottest Steam games launching for ‘Cyberpunk week’, analysis of which games converted Hype to sales and which didn’t, plus access to the Hype back end, Discord & more. So psst, go sign up.]

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