The game is very difficult and extremely time-consuming, requiring at least 300-400 hours of gameplay, including the online trophies, if done legitimately. However, if you manage to find three other boosting partners, it's possible to unlock the multiplayer trophies quicker, bringing the time down to over 100 hours, and therefore the difficulty rating to 4-stars.

Also taking into consideration, however, is the fact that you need two copies of the game in order to unlock the Platinum. Yes, that's right. The Dog Of War trophy is glitched on the disc version, which means you will need the digital copy. And the Always Attack trophy is glitched on the digital copy, but doable on the disc version.

Finally, you will also need a headset for the Platinum.

Since you'll obviously want to get the hang of the game first, we recommend starting with the Voice Command Trainer, which not only teaches you how to play the game and which voice commands to use, but also net you the Communication Officer trophy.

Hardcore is available from the start, and the difficulty-related trophies are stackable. However, if you want to make things easier on yourself, we recommend playing through on Normal first, then a second playthrough on Hardcore. It may be more time consuming, but will save you much frustration in the end. Though of course, the choice is yours.

There are two main sections to the single-player: Prelude to War, which is a prologue campaign, and World War III, which is the main campaign. Both of these will eventually need to be completed on Hardcore. In addition, you'll need to complete World War II on Hardcore with each of the three factions. One tip we recommend, is saving after each game, and reload if you lose a campaign.

Finally, play twenty single-player skirmishes for the Training Simulator trophy. Since you don't need to win for the trophy, you can order your unit to Evacuate immediately after the game begins.

With all that out of the way, it's time to move onto the online. Here is where you'll be putting in the hours. Many of the trophies are quite difficult to obtain legitimately, such as winning three missions in a row for Always Attack (which requires the disc version) as well as Dog Of War (which requires the digital version) and several others, not to mention the difficulty in finding people online to play with who aren't already highly skilled in the game. If you plan to boost these trophies, check out the forums under our Links tab.

With all that completed, simply mop-up any offline trophies you may still be missing, then celebrate in earning one of the more difficult Platinums out there.

IGN has a Walkthrough here:
http://www.ign.com/wikis/tom-clancys-endwar/Campaign_Walkthrough

simula67 has a great Trophy Guide here, which includes the DLC:
http://www.playstationtrophies.org/game/tom-clancys-endwar/guide/

And a Trophy Guide by trophybot:
http://ps3trophies.com/forums/showwiki.php?title=PS3-Trophy-Guides:Tom-Clancys-EndWar-Trophy-Guide

And an Achievement Guide (basically same as the trophies on PS3) by Blue Radium:
http://www.xboxachievements.com/game/tom-clancy-endwar/guide/

Here's a Boosting Forum on PlaystationTrophies:
http://www.playstationtrophies.org/forum/tom-clancy-s-endwar/5800-trophy-boosting-thread-read-first-post.html

And a Boosting Forum on PS3trophies:
http://ps3trophies.com/forums/tom-clancy-s-endwar/6055-official-tom-clancy-s-endwar-boosting-thread.html

Lastly, here's a basic Trophy List:
http://psnprofiles.com/trophies/33-Tom-Clancys-EndWar