Arsenal of Democracy maintains the general look and feel of the original game, but features a number of changes and improvements over its Hearts of Iron 2 starting point. The purpose and end result of these changes was to make the game less management intensive, more user friendly, and through improving the AI, more challenging. The changes were focused around the game's Economy, Production, Combat, Historical Accuracy.
There was an overhaul of the graphics and user interfaces. This impacted many systems including espionage, trade, and notifications. There are increased screen resolutions and a freely selectable window mode.
Numerous mechanics were adjusted. The production and economic now give user significantly more control and had the result of making the AI more competitive when compared to the original Hearts of Iron 2. The combat mechanics, including attrition algorithms, were completely reworked to better reflect realistic unit behavior and losses. The AI was modified to present more of a challenge to players and to adapt it to the new features in Arsenal of Democracy.
These new features include a completely new system, logistics, national ideas, similar to the ones in the Europa Universalis series, an expanded technology system and four new battle scenarios.
There were numerous smaller changes as well, and as with other Paradox Interactive games it is very modification friendly.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Source: Arsenal of Democracy on Wikipedia