This probably doesn't happen to NA players but anyaways I thought I'd share in case the game population expands in the future. Sorry for my engrish, I play from South America and like many other multiplayer games hosted far away I'm used to a bit of lag here and there. Games like Warframe, Robocraft are pretty playable with 150~200ms latency.
Salem is lightweight graphically, but the network part seems to be fragile at the moment. Sometimes I get this black screen with "loading...", it's very quick but deadly if you're in a hurry. As an example, I was hunting rabbits and prepared to run away in case of a Hare show up, when it did show up I ran to the gate but the black screen took over just in time for my plan to fail.
That's one of the reasons I avoid any pvp in Salem, it's just not reliable for some reason.
Recently I also noticed a certain "pause" in the game, this one happens kinda often. You stop moving as if a disconnection happened, then it resumes in about 1~2 sec.
tl,dr: Some games are laggy but constant, so you can adjust to it. Salem has some "spikes" which I can't tell if it's the Java client , or the server, but it makes PvP a "Russian roulette" to be avoided.