Bro you might have lost some of your training but you will most likely get most if it back in few sessions. Should definitely try it again. (There is no escape)
There's no split screen or anything if that's what you mean. But if you have more than 1 computer, there are no issues with lag because the songs are played locally.
You see the other person's score in realtime as you both are playing, but they're slightly out of sync so nobody has to experience any lag while playing