An extremely well written game. 80 days is a game with much love poured into it, I had a hard time trying to stop playing, because I felt so immersed. It can be a bit repetitive when you've played it for a long time, but I absolutely adore this hidden gem of a game. If You like any of Jules Vernes works or just good story driven games, You should buy 80 days.
I personally adore this game, but I can see that it might not be for everyone. If You value good writing and atmosphere in games, this is for You. If You generally love lovecraft or steampunk, this a game I'd highly recommend. If You focus on other things when looking for games, or generally don't like the whole lovecraftian thing, I don't think this is a game for You.. If You're thinking of buying it and can't descide, buy it! It's a lovingly crafted game and definitely worth a try. (Or You could go to Fallen London, a free-to-play web rpg made by the same people. To get som idea of what You're in for.)