i believe batman arkham city will be released in october 2011, its a long wait but hang in there, it looks great and sounds great. it depends on what kind of other games you prefer in order what demos to check out.
Bulletstorm will have an on-line team based mode ( not sure of the name ) but the objective is to get the highest skill point score. Also they will have echoe mode ( you can try the demo on XBL or PSN ). They will probably have the regular mutiplayer modes like TDM and FFA.