The penultimate castle-sim.
I'm going to stop here and mention the presentation first. I recently purchased this in the "Stronghold Collection", so I'm not a long-time Stronghold fan. That being said I think it's important to mention the detail here. The game is loaded with charm, and it's obvious that Firefly put a lot of effort into the details. I love clicking on animals, seeing the cute picture, and reading their silly names. In fact once I mourned a cow named "Big Jim" who was slain in an enemy attack (boy were they in for ti). This detailing was worth mentioning and I wasn't sure where else to put it.
The game is 2D, so of course various things are limited but it still looks quite nice. Animation is kind of stunted, but it's passable. The buildings themselves are well done, and again a immense amount of detail is present. Just watch the bakers at work. Everything's decent and the game has a good art style, it's not the best looking 2d game I've seen (and it's locked at 800x600 resolution), but it's definitely nice looking.
The sound design is solid. The music is typical medieval stuff, and quite nice to listen to. The battles sound epic, and the voice-acting is rather humorous. The ambiance of the surrounds goes well with the sound of peasant hard at work. All in all, it's a pleasing game to listen to.
The gameplay revolves around building castles. Depending on which game mode you play, that's all there is to it or you may have to keep an economy going.
The economy model is solid. Many reviewers have noted that it's rather simple, but that's it's strength. You need food to feed your peasants. There are base foods like apples, and manufactured foods like bread. Bread may be more fulfilling than apples, but while apples simply need to be picked, Bread needs wheat to be harvested, flour to be ground, dough to be made, and then finally cooked at a bakery. The economic model is very logical and in all areas it's like this. You have quick unfulfilling or cheap goods. And long, laborious expensive goods.
Various things keep your population happy like religion, food, tax rate. Inevitably you need troops to defend your castle. Troops require gold. Taxes make people unhappy. Things get more complicated as you get more people or are under siege. Your food dwindles and people become unhappy. There's a cool balancing act that the entire game forces upon you. This balancing act continues to your actual castle, as you won't be able to fit everything inside your castle (Some maps are designed very cleverly with imbalances in mind. Like all the best food spots are yours, but the enemy controls all the stone)
The actual castle building and sieges are great. If you expect to succeed on either the attack or the defense you must carefully plan. The game's isometric perspective has been criticized for making castle building hard. I've never had such problems (pushing spacebar make everything go flat allowing for easy building). Anyway, walls can be built to any thickness or length. It is wise to build walls as thick as possible to help withstand the enemy longer, buying your archers time. There are a myriad of defenses, like killing pits, caged dogs, pitch, moats, braziers (to create flame arrows), boiling oil. The options are numerous and all must be used to stop a determined attack. Do not expect to sit back and watch. This is a hard came and it requires very active and heavy play.
All the units are balanced well. Attacking is definitely harder than defending (unless you rush in a skirmish). My main gripe is that knights are nigh invincible (which was historic, there are reports of knights riding into battle looking like pincushions, yet still uninjured.) archers a bit too powerful (and sometimes not powerful enough), and the Lord of the Castle is far too weak (compared to later games). The game may also be a bit too fast ad too heavily focused on castle assault and not sieges. It's got problems, but overall it's very, very, very well done.
There's quite a bit of replay value here. There's two separate campaign for the game. One economic and one military. There are also independent sieges and invasions for you to play. On the economic side there's even more single missions and a free-build mode. The free-build mode is a lot of fun, and you can still call in enemy invasions at will (make s the game a lot easier and still have some combat at will). I believe that there is multiplayer, but I haven't tried it. There's also a map editor which is very easy to use and assures practically limitless gameplay.
Lastly, there are a few good mods to look for. The best is probably the Lord of the Rings overhaul, great it you want to redo the battle for Helm's Deep, or Minas Tirith.
There's a solid package here. There's a ridiculous amount of gameplay options, the graphics are still quite nice, sound is pleasant which is important in a game like this. It's hands down the best and probably one of the only castle building sims there is. There's not much wrong with it besides, difficulty, and some balance issues. It's well worth getting.