Without VERY decent hardware THIS GAME WILL FALL SHORT OF EXPECTATIONS!!!!!
Overall the gameplay is akin to that of Medieval, the AI is pretty much copy/pasted out of the .txt files of Medieval right into Empire, I, however, have no issue with this, for if you pley on anything higher than very easy that the AI suddenly becomes more than competitive for even seasoned total war fans.
The command board (lower right side of the screen) is a little hairy at first, though the tutorials clear any questions right up.
Though the biggest problem I had was with the hardware I was using. I at first loaded the game onto a machine with Windows XP, and several now old-school techs. For example:
1) Single Core Processor (roughly 3gHz)
2) nVidia GeForce 7850
3) 2 gigs of DDR RAM
I admit this is a pretty decent rig, enough to run pretty recent games, albeit not at the highest quality but they run. Right off the get go with Empire, though, the game would crash instantly following the clicking of the icon. I than proceeded to load it onto a better machine, more recently made. Including:
AMD AM2+ Dual Core 3.8 gHz
and SLI 8800 GT's
with 4 gigs of DDR2 RAM
The experience was completely breath taking. But the point I'm trying to make is that you absolutely need the RECOMMENDED requirements, if anything less, be my guest and try but please don't be too disappointed by the results.
Finally, further into the game the turns take extremely long periods of time, try to keep the number of armies on the map down and the amount of settlements you have can get equally out of control as most of the world is playable. MY advice is to just keep everything in check as you go and if necessary lower the graphics.