Modern20 is a top-down redefinition of the D20 Modern game system. Several sore spots with the system are addressed, and the designer makes some interesting innovations along the way.
The character generation is perhaps the most interesting retooling of the game. It should appeal most to players who like creating characters using D20 Modern base classes; much like Grim Tales, the system does not utilize advanced or prestige classes. This could be a detriment for players who like to “subscribe” to a class concept and don't want to make a lot of decisions along the way.
The most interesting aspect of the character generation system is that it provides in-game representation of what might be considered more mundane aspects of a character's background, and even represents things like occupation changes in play. All told, I think this makes Modern20 an excellent choice for “everyman hero” gaming, where the characters are realistic and well defined characters.
The system does handle many of the hangups I have with the D20 Modern combat system nicely, namely nonlethal damage and firearm rules. However, while the idea of inserting a hit location system into a D20 game had promise (something I do in my own d20 house rules), I think the optional injury rule runs counter to the streamlining he tries to achieve elsewhere.
