I have to say that as beeing Lisboa's smaller brother, they also got the Liboa problem with a not that impressive nightlife. And the nightlife that is, you find in the Dochas, outside the city centre. The restaurants closed a little early, and we did not manage to find any bars or pubs to sit down and relax. You have always the casinos, but that is not a thing for everyone.
As i Lisboa, you have to go to the Dochas, just outside of town to find anything. But even there is/was very little happening while we were there. It was all under construction, and the few places that were open, did not have so many customers. Not even on Halloween. Off course, we still got a little drunk, and had some good burgers, but it was not very pulsating. Not even when we walked trugh the city did we see any bars.
Hopefully it was we that did not know where to go.