this game is basically etrian odyssey on steroids.
the game structure is the same as etrian odyssey -- you create and control a party (or multiple parties, if that floats your boat) in order to explore areas called labyrinths. during expeditions into these areas, your "map" of the area gets filled in (when you buy a map at the store, it just means that you are then eligible to save and remember whatever paths you discover when you are at that area). in traversing these paths, you encounter different monsters which have different strengths and weaknesses.
there are many races and classes (as well as three alignments) to choose from when creating characters, and party creation is made more complicated by this as the game introduces "affinity" -- how well characters work as a team. there's also alchemy, which allows you to create and customize weapons, armor and other items. the game is driven by a quest system, similar to many games. each major rest stop in between areas has quests that you can accept and undertake for rewards and story advancement.
i've played about halfway through the game (i've saved about 40% of the map areas). it's very engaging and addictive if you like this type of gameplay. there's a fair amount of problem solving aside from just straightforward slogging through the labyrinths. i also enjoy leveling up different classes and races and figuring out how to make a better and more efficient party for my style of playing. right now i have two parties, one attack heavy and one defense heavy. i rotate some of the characters every now and then.
the downside is that the game isn't really visually stimulating. the monsters you encounter just sit on the screen and there is not much in the way of battle visuals (sort of like pokemon games). actually the monster encounters as a whole need work -- pressing x a gajillion times each encounter gets tiring. the story is mediocre at best, although atlus did take pains to actually incorporate multiple side stories to explain the different quests. the menu system is intuitive but a little tiring to go through over and over -- some provision for shortcuts should have been provided. (for example, the battle menu should have an auto battle setup. or, the recipe lists should be just one button away from the alchemy screen, and vice versa.) overall, it's the intuitive but clunky menu system that ultimately does this game in. i can imagine that even people who find this game immensely interesting at first will eventually give up without finishing it, just because the menu system tired them out. i'm getting tired of it, and the only reason i'm powering through is because i've seen worse (etrian odyssey, duh).
the verdict? 6.5/10. you really need to love this type of gameplay (big on problem solving, organization, collection, combinations and statistics but lacking in visuals and an amazing story to hold it all together) in order to enjoy class of heroes. this isn't the type of game that just anyone can pick up.
(originally posted on my personal blog: http://miaowow.blogspot.com/2009/08/class-od-heroes-psp.html)