There's very little game to it. It's a physics sandbox like garry's mod, but somewhere in the development process they forgot to add the fun. I wouldn't buy it yet, wait for multiplayer to get added at least.
IIRC the devs stated multiplayer would be "impossible" After a quick search, they are going to add multiplayer but not until the core gameplay/engine is completed, AKA not for quite some time.
It's nice if you like realistic driving games, other than that there's not much. It's one of those games where you have to make it fun for yourself. There's scenarios that you can do right now, but they're mostly races and get from point A to point B.
The modding community is... decent. You have some pretty cool stuff coming out of the community(IIRC someone made a mod for a plane, it was awesome) but I haven't seen much out of it in a while.
Performance wise, it doesn't run that well. as Block said, doesn't run well on budget PCs.
TBH I find it fun even if it's extremely basic at this point. I'd wait a while to buy, however, as there isn't much to do and it kinda gets lonely considering how big the maps are.
