I recently found these two gems:
My question is: How are the physics with so many elements efficiently handled? Am I just severely underestimating modern computing power or is it possible to 'just' have a two-dimensional array, each cell of which describes what is placed at the according position and simulate each cell in every step. Or are there more complex things being done like summarising large areas of the same kind into a single data set and separating said set as needed?
Are there any open-source games like this I could look at?