Hi! I used Haxe language and HeapsIO engine. It’s all using my open-source code base “GameBase”.
Apart from the rendering engine (HeapsIO), everything else is homebrew, including the physics :)
The source code is available here: https://github.com/deepnight/ld48-NuclearBlaze
And my physics engine is explained here: https://deepnight.net/tutorial/a-simple-platformer-engine-part-1-basics/