Medieval Fortress (31120 "Medieval Castle" Alternative MOC), by mocscout

This MOC uses three 31120 sets for its construction, without needing any extra pieces, and it's pretty good considering everything that's built with the set pieces. However, this restriction is noticeable in some details of the assembly, where the most indicated piece wouldn't be the one used but the one that was effectively available.

It's not perfect, but it's a good alternative for those who want to have a castle for the Black Falcons.

There are some sections that can be improved (and I'll talk about the worst one later), but in general it's a very good construction, especially the aspect and detail of the walls, as well as the turret.

It's a very robust set, with a very well built-up base, giving the castle a certain dimension and grandeur. The interconnection of the base with the vertical construction of the MOC is well done, and it's sturdy enough to take the MOC by the walls and lift it up. It can be transported without any fear of disconnection, but one must be careful with the upper sections - roofs, battlements, etc. - which are indeed more sensitive.

There are two assembly instructions, the original mocscout one and a "friendlier" and updated version by Razgamaziel which provides a more dilated assembly, in its 202 steps, and is easier to understand. I advise the construction according to this last version.

Even so, it is possible to find several errors or omissions whose solution implies some detective work to understand the assembly sequence or to advance some steps to understand the location of certain parts. But that for people with an average level of experience are relatively easy to solve.

Two examples of this are the 41 pieces in step 11 which are only 40 (and you'll need all the six that are left!) and in step 89 where the location of a 1x1 and 1x6 plate are blocked by another piece and only in step 95 you understand where they are. 

It's not a very playable MOC, but you can still have some fun with it. The MOC has areas that are inaccessible, both in the bases of the two front towers and in the two rear rooms it is complicated to put anything there and seeing what they're not easy either.

Similarly, the rear room on the 1st floor is also of little use, with a ladder and the support structure to the upper floor in the centre making it unusable.