The Binding of Isaac: Rebirth
This is an extended version of the famous Flash game “Binding of Isaac” by indie legend Edmund McMillen. My task was to port the game code from Flash/ActionScript2 to KAGE, a proprietary cross-platform C++ framework, adding heaps of new content and innovative new gameplay elements.
I started working on this project for Nicalis, Inc. in 2013. While I started out alone, over time four new programmers were added to the project and I took the role of a lead programmer, assigning tasks and giving instructions.
I also had to work closely with the lead artist, Matt Kap, who was tasked to re-create all Adobe Flash content in a new art style, for the new engine. Adrian Gavrilita and I invented a new file format, along with a tool for creating multi-layered 2D sprite animations. This custom tool, mostly written by Adrian, helped a lot with asset creation.
One interesting challenge was to adapt all the gameplay systems for seeded random number generators (RNGs). In Rebirth it is ensured that if you replay a game using the same random seed, all random-chance events will have the same outcome as before.
After release of the game I also took the lead in handling bug reports/customer complaints for the PC version, and created a thread on the Steam community boards which helped a great deal in resolving common issues. Initially the game did not run on pre-OpenGL 3 hardware. I managed to lower the requirements to OpenGL 2.1 post-release, which resolved a lot of customer complaints and extended the potential player base significantly.
Afterbirth expansion (2015)
In the second half of 2015 I stepped in as a lead to finish the official expansion “The Binding of Isaac: Afterbirth”, which adds several new features. I was in charge of implementing seed-based daily runs with leaderboards, and a new game mode called “Greed Mode”. At the same time I was also assigning tasks and helping out with implementing new items and bosses. After release of the expansion I was again heavily involved in bugfixing and handling customer complaints.
New Nintendo 3DS port (2015-2018)
I was also heavily involved in the New Nintendo 3DS port of The Binding of Isaac: Rebirth. One very interesting challenge was that the 3DS graphics hardware does not support pixel shaders, but I was able to emulate some of the shader effects using color combiners. The 3DS port was released in the second half of 2015 and subsequently improved with multiple patches. In 2018 I picked up the 3DS port again because Nicalis wanted to do a physical release.
Repentance expansion for Nintendo Switch (2021)
The Binding of Isaac: Repentance was created over the course of many years by the original developer of the Antibirth mod and his friends, and finally released in 2021. I was then approached by Nicalis to port this new version to Nintendo Switch.
Compared to Afterbirth+, which had already been ported to Switch, Repentance added complex visual effects and huge bosses, resulting in unacceptable rendering performance on Nintendo Switch. I spent a lot of time with a GPU debugger to find and fix bottlenecks in certain areas of the game. It was released for Nintendo Switch in November 2021 (digital version) and December 2022 (physical version).