GODOT is my favorite engine. It's great for 2D and has a lot of great free extensions and templates you can use!
Languages: C# or GDscript (basically python-lite)
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GDEVELOP is useful if you are a complete beginner or don't know how to code. (It's like Construct, but free and open source).
Languages: Event-based, no real coding
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UNREAL is best for 3D. But exporting an asset-heavy build can take hours to a whole day. (Keep that in mind when scheduling your time.)
Languages: C++ or "Blueprints"
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UNITY...is like the in-between. It's less powerful than Unreal, but doesn't force you to either recompile the engine or use visual scripting. It's more complicated than Godot, but has better 3D capabilites. Unity has a lot of tutorials and *can* be good for collaboration (sometimes...when it feels like it). If you go with Unity, just make sure everyone is using the same version and tell everyone NOT to upgrade during the jam. (Sorry, I'm not a fan of Unity.)
Languages: C#
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And if you can't code or make art, you can use:
TWINE is an open source engine to make interactive stories. No code or art required! (Though you *can* do both as it loads straight to HTML.)
Languages: None required, HTML or CSS optional