It's a short game with simple puzzle gameplay. But it requires that you to go outside the game to get information (Kyiv train station street name) and access an actual website to get vital information for the game and send an actual email to an address you find in the game. If that website and the email address go offline... the game will become unsolvable and unless a walkthrough has the response emails you'll miss out on content important to the story. Not good for a singleplayer game.
