During the development of Balatro, Local Thunk avoided playing roguelike games—with the exception of Slay the Spire.

Balatro developer Local Thunk has published an extensive history of the game’s development to his personal blog, in which he admits he didn’t play any rogue-like games at all during Balatro’s development…except one.

In his development timeline, the anonymous developer says as of December 2021, he made a conscious effort not to play any more roguelike games starting from that point.

“I want to be crystal clear here and say that this was not because I thought it would result in a better game, this was because making games is my hobby, releasing them and making money from them is not, so naively exploring roguelike design (and especially deckbuilder design, since I had never played one before) was part of the fun for me. I wanted to make mistakes, I wanted to reinvent the wheel, I didn’t want to borrow tried-and-true designs from existing games. That likely would have resulted in a more tight game but it would have defeated the purpose of what I love about making games.”

However, a year and a half later, Local Thunk broke their rule exactly once. He downloaded Slay the Spire. “Holy shit,” he wrote. “now that is a game.”

He goes on to explain why he started playing in the first place: “I did this because I was having some troubles in my controller implementation and I wanted to see how they handled controller inputs for a card game but I ended up getting sucked in. Thank goodness I avoided playing it until now because I surely would have just copied their incredible design (intentionally or subconsciously).”

Local Thunk’s post-mort is full of interesting insights. For one, he explains that early on in development he named the production working folder for Balatro “CardGame” and then just…never changed it. He also reveals that the working title for the game throughout much of its development was “Joker Poker.”

Local Thunk also provided a number of insights into scrapped features, including:

• “a version where the only way to upgrade anything is to upgrade the cards in your deck in a sort of pseudo-shop, and those cards can be upgraded multiple times (think like Super Auto Pets, pets have different XP/levels when combined, same idea)”
• “a separate currency for rerolls outside of %1quot;
• “a ‘golden seal’ to be added to playing cards when you skip all blinds that returns that card to hand after it has been played”

We also got treated to an anecdote on how Balatro landed on 150 Jokers. It was apparently the result of a miscommunication:

“I also had a meeting with Playstack [the publisher] this month [October 2023] where I described to them the final content in the game, including ‘120 Jokers’,” Local Thunk wrote. “Later that week I had another meeting with them, and someone mentioned something about 150 Jokers. I couldn’t remember if I accidentally said I was going to make 150 or if they misheard me, but either way I thought that 150 was a much better number so I added 30 more Jokers to the plan.”

Finally Local Thunk provided the deep origin story of the name…Local Thunk. tl;dr, it’s a programming joke:

“My partner was learning to code in R at the time, and she asked me ‘How do you name your variables?’ I went on some rant about casing, using descriptive words, underscores, etc. She waits until I am finished and says ‘I like to call mine thunk’. I thought that was just about the funniest thing I had ever heard.

“The way variables are declared in Lua is (sometimes) with the local keyword, thus local thunk was born! I wouldn’t choose this name for quite a while yet but this is the moment I looked back on when I was finally ready to create a developer handle online.”

There’s a lot more to read about the making of Balatro in Local Thunk’s blog, which can be found here. Needless to say, we love Balatro at IGN, giving it a 9/10 and calling it “A deck-builder of endlessly satisfying proportions, it’s the sort of fun that threatens to derail whole weekend plans as you stay awake far too late staring into the eyes of a jester tempting you in for just one more run.”

Rebekah Valentine is a senior reporter for IGN. You can find her posting on BlueSky @duckvalentine.bsky.social. Got a story tip? Send it to rvalentine@ign.com.