Good Idea, Solid Gameplay, Bland Execution
I would like to start by stating that there is nothing fundamentally wrong with Puzzle Quest: Challenge of the Warlords. Anyone who likes Bejeweled will almost certainly like Puzzle Quest and the game certainly gives enough content for its price, especially if a player does the sidequests. Spells add a noticeable amount of strategy to the Bejeweled formula and can often be combined with each other for great results; every spell has its uses and the spells are surprisingly balanced. Customization is about as good as it can be in a puzzle game, allowing players to choose from a fairly wide selection of avatars, four different classes, three difficulty settings, several different turn time limits (or none at all), and a toggle-able 'hint arrow' that points out possible moves if the player doesn't find one for a while, which all make the game equally accessible to veterans and beginners alike. Unfortunately, while the core game is solid, everything else feels either questionable or simply lazy.
Puzzle Quest is exceedingly lacking in terms of aesthetics. The backgrounds look nice enough and I will give them credit for having a fairly large amount of enemies without resorting to recolors, but that's about the only praise I can give it. The still-pictures of the characters aren't drawn bad, but none of the characters have more than one pose and they all look like they are directly from Flash games. Once in combat, there is absolutely no animation on the characters' part, which is a shame since even all the way back in the SNES/Genesis era it was common for sprites to interact to how the battle was fairing in games such as Tetris Attack! and Kirby's Avalanche. Music has next to no variety and none of it is even remotely memorable. The voice acting of the narrators is also rather subpar as it is both cliche and overacted, but such events are thankfully rare.
While Puzzle Quest certainly has plenty of dialogue, it doesn't change the fact that the story falls flat on its face. In typical fantasy fashion, you are a person who shortly after officially becoming a knight is entrusted with saving the world, this time from the lord of the undead. The way the story is handled is rather awkward to say the least, as you go from constantly reporting clues as to why the undead are attacking to your queen to just sort of stumbling from town to town helping people with whatever is bothering them until "oh hey it's the undead citadel!". Many companions have game-spanning sidequests related to them, and some of these are surprisingly interesting, but the conclusions are often abrupt and unrewarding, both from a plot-perspective and a loot-perspective. The game certainly tries hard to have humor, mainly from the snarky main character, the gluttonous Drong, and the talkative Khalkus, but rarely are such jokes actually amusing and jokes that rely upon each character's quirk get beaten far beyond death (i.e. the fact that something to the tune of 10 sidequests involve Drong wanting to eat something weird). In other words, while Puzzle Quest certainly has RPG elements, a strong story is definitely not one of them.
Moving around the map is more of a hassle than it should be. Enemies spawn along paths over time and while at times they can be avoided via alternate paths, often even the alternate paths are swamped with fights. Add in the fact that several quests in both the main and side storylines require the player to backtrack a fair amount, fighting can get more than a little tedious at times. Fights can thankfully be bypassed with a mount, but getting a mount requires fighting the same type of enemy three times, solving a puzzle to capture it, and then leveling it up. Leveling up a mount lets you bypass stronger monsters on the map (in addition to giving stat boosts in combat and a mount-specific spell), but leveling requires fighting versions of the mount which gradually become stronger with shorter turn time limits over and over, which often becomes very repetitive. Thus, one becomes stuck between fighting the same enemy types over and over while going back and forth or fighting marginally stronger versions of the same enemy over and over to bypass them.
The game is peppered with several other mild annoyances. Many companions are given to the player at inappropriate times most notably Syrus Darkhunter, who deals 10 damage to undead at the start of combat, since he joins near the start at around the time the game shifts from fighting undead to fighting orcs and undead don't pop up again in any significant amount until the very end, at which point 10 damage becomes nearly negligible. Gear is often situational at best, meaning the rewards from many of the longer quest chains are used only once or twice, if at all. The castle siege system seems to be just thrown in since it makes absolutely no difference to how NPC's react to you (in fact Khalkus increasing the damage you deal to machines and cities means he cheerfully lets you siege his home) and brings down the story even more since the player is supposedly only a knight and both friendly and hostile cities can be captured just fine, and all it gives is a small gold boost every once in a while when the player goes to the city. The leap in difficulty between Normal and Hard is also a bit overly much and it would have been nicer if Hard was tuned down a little or preferably if a difficulty had been added between the two. Finally, the AI sometimes 'cheats' as well, as it will at times pass up a great opportunity for a lesser boost that just happens to lead to unseen gems falling into the grid in such a way that they make a 4 or 5-gem combo resulting in an extra turn...about 5 times in a row and taking away over 1/3 of your health in the process; it is understandable that the AI needs to be given some advantage over human players, but it would make more sense to at least provide some sort of non-interactive representation of the next line of gems or some other function similar to the way most puzzle games let players see what the 'Next' piece is (such a thing would also greatly reduce the amount of luck involved in general as well).
Ultimately, Puzzle Quest manages to successfully blend the puzzle aspects of Bejeweled with plenty of RPG elements and for that alone it certainly deserves praise since all too often games fail when combining two genres. So, for any fans of Bejeweled, or even puzzle games in general, as long as you can deal with a few questionable design decisions and the lack of any real style or charm to the game, the amount of content and customization available is certainly more than large enough to warrant a purchase.