The one and only problem I have with this game is if you forget to pick up all the stars upon completing an objective you miss out on a gold medal and are forced to replay the mission (providing you want the gold medal of course.)
I give up getting the hard achievement.
I want to like this game, but controls are too stiff for me to keep playing. Levels are a bit flawed in some places, it's too memory based for my liking.
You can revisit areas to capture warehouses you missed, each zone is different as to where the warehouse is, so just go Ramble and try each area until you get the objective for capturing the warehouse.