That would be a short one:
1. Wow, that was fast! Tested it, seems to work fine. I would propose you add more skills to round them to ten (for example Leach- recover one HP on enemy kill if life not full) or even a dozen, but otherwise things look great.
Edit2: You should really put somewhere a note how much XP you need for each level. Otherwise it's a trial and error thing.
Edit3: Think about implementing the option to choose how much XP is received by an XP scroll. Right now it's unclear how much you receive and it makes very little sense to be able to assign a value on enemies, but not on the scroll. If you implement this it will be possible to make a game where you receive no experience by defeating enemies, but by finishing a task(where you receive an XP scroll on completion).
2. I did not explain the image part as good as i should have. By image I mean a pixel art image. Something like 64x64pixel png file with limited palette, which would keep the retro feel, be in line with your faux screen resolution and doesn't blow up the game size. I love how everything is encoded in the url, so I wouldn't want to make it too big either :)
3. Tested, armor seems to work fine, maybe just introduce a second set at some point.
4. I think 4 would be enough, if you make it one of each type: one normal, walkable, one animated, walkable, one normal non walkable(wall type) and one animated non walkable. This would actually increase variety in levels immensely.
Edit4: Another thing you can do is putting a checkbox "walkable" under the pixel art editor under the "Merge with adjacent tiles" checkbox. It would serve two important purposes- first, it would make obvious at a glance for new users whether or not the tile is something you can walk over on the map, because sometimes it's not clear. Second, checking or unchecking it would allow for users to repurpose walkable tiles into non-walkable tiles(and vice versa), giving you more tiles of the type you need(not every map requires equal amount of both) without increasing the total.
As for using NPC's- yeah it's a nice workaround(sometimes). I use them as collectable items :) It's too bad they are limited in use by the fact that you can only mark them to disappear after the first dialogue. Would have been very useful if that was available after the alternative dialogue too.
Oh and nice game BTW(the one you linked)
5. Thanks. I was trying to think of a way to make a slightly bigger game, without changing the 3x3 map grid (which I generally like). I came with the idea to use a simple .html page as a level selector but the fact I couldn't move experience and items between the levels put a damper in it.
PS: Would it be possible to decrease the size of the "!" that shows a point of interest in game (new dialogues)? I get it's a good size for visibility, but it's absurdly big right now- it's almost as big as the default character sprites and actually bigger than the ones I'm using right now. Perhaps keep it 1/2 of that size, but give it an effect or 2 frame bobbing animation to make it stand out...
Edit- fixed an error
Edit2- Added a suggestion on XP leveling requirements
Edit3- Added suggestion on XP scrolls
Edit4- Added suggestion on tilesets. Edits are now bold for clarity when reading.