Apparently Netherrealm wasn't expecting Mortal Kombat to be as popular as it has been, and is rapidly putting together a patch to help the straining multiplayer cope with the load.
The patch was announced with a statement on the Mortal Kombat message boards (registration required).
"Mortal Kombat has millions of online matches being initiated worldwide every day, and we have run into some unanticipated technical issues," it read.
"Warner Bros. Interactive Entertainment and NetherRealm Studios are aware of the issues with the online gameplay – specifically with 'King of the Hill' and Ranked 1 v. 1 matches - and we want to assure our fans that we are focused on resolving online issues ASAP."
Single-player and local multiplayer are apparently unaffected.
A technical issues forum has been added to the boards to collect more information on the problems. Updates are expected over the next two weeks.
Mortal Kombat released last week on PlaySTation 3 and Xbox 360.