It was playable, a couple of times. Freebuilds which involve a set castle are not generally popular, since there is only one way to play that landscape. On your next freebuild, try making a Place Your Own Keep map. Those are much better received. :)
Future note: don't place too much iron or stone (or much of anything) in huge clumps, it's very visually downgrading, and is just "too much" to be honest. If you do want that much iron, spread it out over the map more.
Using bridges on your first map? Good work!
Map Design: 3
Pretty plain fields, try adding grass and dirt areas in flatlands, and maybe the occaisonal tree. The mountains were fairly well done, but more elevation variation with the equalizer tool, and rocks, and they'll be even more awesome!
Got to work on this part, it's 20% of your rating, and leaving it out is not good.
Very good first map, my first wouldn't even match this one! Well done, and keep going. Upgrade your abilities as you make a few more maps and you'll get good ones out soon. And be sure to spend hours on maps as well, it also greatly boosts your design.