As it is evident from the promotional clip below there is a lot more to Portugal besides Lisbon. A local I spoke to, even described Lisbon as overrated and extremely pricey compared to other parts of the country. Especially the northern part of it is supposed to be really beautiful.
I will definitely not take his word for it and rather go check it out on my own. Considering I really liked Lisbon I think chances are I would also like the rest of the country. Portugal, I will definitely be back for more!