What anime is this if u know plz help.?

ok there was an anime that i was watching when my computer crashed and i lost its name. it was futeristic. the main character is a guy and he protected cities and stuff from giant mutant looking bugs. i think its in the first 2 episode where he saves this girl cuz the get into a fight and they pull out there coll weapons and break part of a builing and he speeds over and saves her from falling rocks. sooo if u know what anime im talking about or anything that sounds similar plz let me know. thnx.