They doubled their share of votes, that’s Harley a failure. They also have enough votes to be a pain in the butt. The seats come with offices, employees, discretionary spending etc. The AfD will be able to further build their networks and base.
AfD and the Linke (Left socialist party) together habe more than 1/3 of the seats. That means no changes to the constitution or flexible spending without the approval of either.