So, there are two locked doors I haven't found a way to open in Act 1.

The first, is the door to the merchant as you enter the town of Flotsam for the first time. ie: It's the "bag" icon you first encounter as you enter. You can see the "bag" icon on your minimap, and if you go up the stairs to the second floor of that building, the door is locked. As far as I can tell, it stays locked during the entire Act, as I'd go back and check it often.

The second, is the locked door at the end of the cave underneath Flotsam. This is the cave that hippy Elf girl was sending poor human guards into as target practice for her filthy elven scum.

Anyone know how to open either of these?

I don't know about the first door, but for the second, are you talking about the trapdoor? I can't remember a different door in the cave, so either I'm forgetting, or that's what you're talking about.

Minor Spoiler------v (not really)
If that is the door you're talking about, my guess is that the trapdoor just leads to behind Loredo's house. When I was sneaking behind there for the main storyline quest, I found a trapdoor that was also locked, and as far as location, it seems likely they are the same door. Why does that door exist? I have no clue. Were they smuggling stuff? I can't remember.

Might have a point about that trapdoor. Wonder if there's ever a use for it, or it's just something that adds atmosphere.

Still never figured out how to open the locked door to that one merchant though. I can't imagine they placed a merchant in that house and then decided never to let you access him. It's funny, too, because sometimes at night there are NPCs standing outside the door, obviously unable to enter to go to bed. ;p

There is a DLC merchant, for people who bought from one retailer or another, is there not? I suspect he's in that locked house and you can't get in unless you have it.

Well, that would explain it then. :p Confirmation here might be difficult since this is the GoG board. Bleh.

Nope, the DLC merchant hangs out at the place where that merchant goes THE MUTANT'S PERSUING ME!!

It doesn't make any doors unlock.

So, the door to the house on the second floor that that merchant you described is hanging out in front of is still a mystery! :p

It's not that merchant though. Mysterious Merchant in the 1st chapter is standing near the entrance, where you first entered flotsam. He is on that patio, where is that guy who says somethis like: "Help, mutant is harrasing me".
There are no doors so that cant be the place.

Bump.

So, did anyone find out about the merchant in the locked house near the harbor (where you first enter Flotsam as desribed in the posts above)?

It IS annoying. The minimap shows a merchant to be there but there seems to be no way to get to him.

Sounds like the door I'm having trouble with. I can walk almost in front of it (Feels like I'm partially blocked by an invisible object). "Open" appears, but when I click it, it becomes "Use" and Geralt plays with the torch nearby. Any way to actually get in there?