"This is massively important; if it’s mario kart she is possibly unhinged, if it’s something like Fallout or Skyrim then 15hrs barely scratches the surface."
Totally with Mustang on this! Currently on my 4th playthrough of Fallout 4, and am well on my way to beating my last one which took me just over 450 hours. (I build a lot.)
I've been gaming since the mid-'70s. I worked as a games journalist, then a tester, then a producer, then a designer, and then the owner of two companies; one a PR agency, exclusively serving the games industry, and other a development studio.
My partner started as a games writer, then a highly sought-after incubator, then a publishing director, then a CEO.
We both became very successful consultants, and built teams for quite a few massive world-famous games, and plenty of less well-known ones. Our decades of expertise with videogames has allowed us to live and work all over the world, with some of the most awesomely talented people around. Not just in the games industry but in TV, movies, and music too.
I'm now in my mid-50s and I still adore playing videogames. My partner still loves playing too. Our son (in his 30s) is also a gamer. We are highly responsible adults who work hard, and believe we deserve to spend our leisure time exactly as we please.
To the OP; your daughter is adult enough to work, to pay taxes, to get married, to bear children, to drive, to fight for her country... and yet she's not adult enough to choose how she spends her free time? Really?
It's her life, not yours, and while I suspect that your concern may come from a place of love, it's really not for you to decide how she spends her time. So yes, I believe you are being completely unreasonable by not only declaring your daughter to be lazy - simply because her idea of downtime is different to yours - but also, by asking a group of strangers to judge her too. In some cases, pretty harshly. In what world is that kind of behaviour OK? 