If you have not used an app in a while delete it. Videos take a lot of space. Not sure what memory capacity you have but a few videos/movies can hurt a 16gb iPhone's memory capacity
Are you trying to tell me your apps are taking up space on your phone?
Its ok.... They do that. If you need more space delete the one you don't want or buy a phone with more storage.
Dive into mctubes settings and see if there is a way to clear data/cache. This would be within the app or under settings main menu toward the bottom. I don't have the app to look.
If you can't find anything then delete and reinstall the app.
In either case be prepared to lose anything that's saved to the phone itself. Most apps you can't even notice.