Hmm, that's weird, it should work. If you open the files in, say, image editor, do you get corrupted images or see the pictures properly? Because if you see the pictures properly, then git lfs is not the issue, but something else.
If you have all the required tools installed, the list of command should be the following:
git clone https://github.com/jani-nykanen/one-last-adventure.git cd one-last-adventure make make server
You can check that git-lfs is installed properly by typing " git-lfs " to the terminal. If it says the command is not recognized, then git-lfs is not installed properly.
Then you should just open the browser and type localhost:8000. It might be needed to open the web console and disable cache in "Network" tab.
Speaking of the web console, if you open the web console (Ctr+Alt+I), do you get some errors? If you only see the white bar, it should mean that some files failed to load. Other option is that you have incorrect version of node-js installed and TypeScript compiler produces faulty js code (very unlikely, though).