Find your line.
Opening the game. Choose Enter game if this screen stays here.
Playing a downloaded copy?
Open the folder containing game in a terminal and
run:
python3 -m http.server 8768 --bind 127.0.0.1
Leave it open, then visit 127.0.0.1:8768/game/. If the port is busy, choose a free port in both the command and address.
Python is only needed for this local-server option. Playing online opens a different site; local saves do not transfer automatically.