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Clone of Sonic The Hedgehog engine, made in Common Lisp (mirror from GitLab)
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Written by Lucas Vieira <>

What is this?

This is a clone of Sonic The Hedgehog's Sega Genesis engine, which aims to replicate the physics of the mascot's classic games as much as possible.

Why Common Lisp?

There are two reasons for that. First of all, Common Lisp is generally an underrated language, for those who never tasted its power. So, after thinkering with it for a few months, I decided to develop something that would make me sweat my shirt a little more.

Which leads to the second reason. Lisp in game development is not news for me. For the past few years, I've been developing generic C++ game engines and trying to emulate Sonic engine on them has been a personal goal, which I've always set as one of my proof-of-concepts for this kind of project: if it can run such a complex platformer, then it works. The second version of one of my engines also included the ability to run Scheme as scripting language; however, the effort of embedding such a language in a C++ program seemed always so big, and while it did not perform well due to design and implementation choices, there was just so much friction in just enabling those scripts so they can work with in-game objects.

Hence enters Common Lisp. While not a minimal language like Scheme, Common Lisp is just as mature and has so many powerful tools, either on the language or external, which fed my needs for game development. So, if we add these tools, take a good implementation, and then take a mature engine which Lisp hackers use for developing their own games (yes, Lisp game development is a thing), we get stuff like this project.

I am definitely biased on those terms but, if you came here looking for game development stuff, I tell you right now: why not take Common Lisp for a spin?


Why didn't you use <insert some other dialect here>?

Basically, because I wanted to use Common Lisp. You see other game developers using specifically Common Lisp? They're kind of rare, you know. Most just go with what everyone uses and try to use something that underneath is Python, Lua or anything else. And well, you know, just because something isn't very popular, doesn't mean it's bad nor inappropriate for the job.

Why don't you try <insert some framework for other dialect> too? It's super easy to use.


Why didn't you use <insert non-lisp-y language with Lisp disguise here>? All the cool kids are using the base language, you get the best of both worlds!

It's not Lisp.

Why not just use JavaScript?



As per trivial-gamekit's requirements, in order to run the project, you will need:

  • A x86_64 operational system (Windows, Linux, OSX)
  • OpenGL 3.3+ support
  • A x86_64 Lisp implementation (specifically SBCL on CCL)
  • Quicklisp

Installing Quicklisp

You will need Quicklisp in order to perform the next steps.

For more information, check this page.

Installing cl-bodge and trivial-gamekit

The package itself depends on trivial-gamekit, a layer of abstraction built over the cl-bodge engine.

For more information, check this page.

Running sonic-lisp

For starters, either clone this repository on your quicklisp/local-projects directory, or create a symlink to the cloned folder on your quicklisp/local-projects directory.

REMEMBER THAT THIS REPOSITORY USES GIT LARGE FILE SUPPORT, so you will most likely need to enable it in order to fetch assets such as sprites, backgrounds and sound effects!

Then you can load the system and start the game:

(ql:quickload :sonic-lisp)

Anytime you want to quit, either close the window or type the following in the REPL:



Currently, the project is very poor on documentation, this is due to the fact that it's still highly experimental.


This project is distributed under the MIT License, except for eventual copyrighted characters (Sonic's sprites, some sound effects, etc). Specifically for the code and for the code only, check the LICENSE file for details.

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