In the month since launch.
Worms Rumble has been out for one month and the response from the Steam community has been pretty rough. While those who did purchase the game appear to really enjoy it, with an 83% mostly positive rating, a low starting population has since plummeted heavily with the game now struggling to get far into the triple digits just a month later.
Peak Worms population back at launch hit 767 players and has spiraled downward since. The 24 hour peak as of this writing is sitting at 221 people while there are 90 concurrent playing at the time of publishing. There are a fair few reviews that mention long queue times but they aren’t a large portion of the recent reviews.
Presumably the game’s population is much better on PlayStation where the game was given away day one to PlayStation Plus subscribers. Since there are no active player counts on console it’s much harder to determine what the actual numbers are.