I was wondering how realistic https://atc-sim.com/ is. I only play for fun, not for training, but I want to play as accurately as possible.
Not very realistic.
- it's text-based; no readbacks.
- there are no approach clearances. You can assign speed, altitudes, and headings, but there is no way to instruct an aircraft to execute a specific approach.
- there aren't, really, any missed approaches or go arounds
- no emergencies
Basically, it' just a game of "keep the aircraft separated", but it doesn't properly simulate how ATC works.
As Digital Dracula says, it's just a game. The best way to experience something approaching the real deal is to join the VATSIM community. It's a virtual ATC system that integrates flight simulator players in a live dynamic ATC environment. It's much closer to the real thing because it's real people, some of whom are real controllers, and you can play it as a pilot using ATC services, or learn to be a controller yourself.
Be aware that the learning curve will be pretty steep compared to a stand-alone mental gymnastics game, because the participants make an effort to make things as realistic and true to life as possible, and as I said, a lot of real controllers participate and provide training tutorials and other resources.
I've played atc-sim for fun myself some time ago, and it can be a nice way to pass time. However, in terms of realism, it only simulates a very narrow range of the tasks real controllers have to do. It gives you a (very basic) idea of what vectoring is like, and that's it. I'd say probably about 5% of what a real controller has to do is simulated, and given the text based interaction, even that part is not very realistic. So all in all, a fun game, but not at all realistic.