This is a copy paste of what I wrote on the Steam forums about the mod:

Hello good people of the forums and fellow fans of the series who still visit this game's forums on here, I have returned and have made good on my promise to make a mod for this game, and finally after a few months (it only took me a month to make it) and some playtesting today I deemed it worthy to post it here.

So here is the download link: https://www.dropbox.com/s/hd3y120tm649rav/mods.gs1?dl=0

You just simply have to put it in your game directory, and that's it.

Here are some screenshots I took today: http://imgur.com/a/JVVbd

Everything should be working properly for you as it's working properly for me.

The mod features: Cossacks' pallisade walls, a missing passive defense I thought was needed in order to combat the Native American AI.

Indian Trade post now is also available for all European nations.

Experimental Guard Tower only for England taken from Hawk's European Warfare, so credits to them for the assets.

Issues: Sadly like with anything else, the mod has issues. One of which is a missing icon for the transformation of the gate, at the current moment it's just a black box, as well as the Open/Close ability for the said Gate when it's built, I cannot change these for now because I can't access the .gp file containing the icons which the game uses.

Strangely enough the AI didn't attack me due to some unknown reason so it might be because it can't outflank my forces or my town anymore, or the walls are just messing with it, I am not really sure.

The Guard tower is only limited to England, but since it's role is sort of the same like the Level 2 Blockhouse I didn't make it available to anyone else as I said, it's just an experiement, I might remove or leave it in the future.

A friend of mine who also playtested the mod for me reported that once he tried to delete the wall he crashed, but after I tried it today nothing happened so I am not sure of what's causing that as well.

The AI cannot attack the walls, and I have no idea or time on how to modify it.

The walls, trade post and Guard Tower are not touched by any upgrades, meaning you will always build them at the same speed and they will always have the same Armor/Defense and Hitpoints, listing custom structures to upgrades in order to improve them has turned out to be quite time consuming and confusing for me however, I might change them in a future update.

Future plans: For now this is only a Prototype or as I like it call it "Phase 1", Phase 2 will contain a few more changes such as buildings providing bigger population caps as well as European Nations being able to produce 17 Century muskets from the Lvl 1 Blockhouse and 18th Century muskets from the Lvl 2 Blockhouse, improved music and so forth, and Phase 3 is going to be polish like different and more music, improvement on sounds and so forth.

I highly suggest you guys also use the musket sounds and music from my sound pack assembled from HEW and HDN here: https://drive.google.com/open?id=0BzLFE2mZAMHrfm14cjlqWWxNNFY4UllRRTZQb3V2V2JES1RxdlRZQktlb3VONk51ZFpqOU0

Since the default sounds are like a horse dying or something, it's harsh on the ears at least to me.

This is all for now, I am unsure that I will continue to work on the mod but this is what I had planned for it, my main problem is limited knowledge on the engine and how to fix bugs and limited time, but if anyone wants to try his hand or wants to modify my work, go right ahead. However I do respectfully request that you provide proper credits if you are going to post it anywhere, that is all.

Cheers and have a nice day!