Children of Mana is a simplistic hack 'n slash RPG that quickly becomes repetitive and a chore to play.
The story in Children of Mana breaks no new ground, serving only to set the backdrop for the different environment in the game. It revolves around a psychopathic demi-god hellbent on flooding the world with Mana, destroying/purifying the world in the process. Your character, one of 3 choices in the beginning of the game, sets out to stop him (obviously).
Your quest takes you to a variety of locations such as an Ice temple, a Desert, a Dark Cave, and even a few traditional dungeons. Each location is remarkably similar to the original Diablo, just without the fun. Each 'stage' consists of numerous 'levels' in which the objective varies occasionally from killing all the enemies to finding the key that opens the potal to the next level, where you do it over and over until the end of the stage. Every 4 levels you are given the option to Save, change equipment, or return to town. It is important to note that choosing the "return to town" option in order to stock up on potions or gear means you lose all progress in the dungeon and have to begin again at the beginning when you return (with all the enemies respawned). In this manner the game quickly gets repetitive since the stages quickly increase in size, numbering up to 20 levels per stage, culminating in a simple boss battle.
Combat, as alluded to previously, is incredibly simplistic, involving merely facing your opponent and hitting the attack button over, and over, and over to string together rudimentary combos. While you begin the quest with only a sword, over the first few stages your character acquires a few new weapons which, unfortunately, do little to improve gameplay. They are mostly used to solve simple puzzles in the level. Almost all of these are optional and simply involve using the hammer to smash the big rock blocking the room with the treasure chest.
Another one of Children of Mana's numerous problems is the uneven difficulty. Children of Mana is a short game, which is made even longer because of the constant, level grinding required to advance. Early on, stages are short and easy (4-6 levels), but after a little while the monsters on almost every new stage make ridiculous level jumps that force you to repeat old stages to gain a few levels in order to advance. However, once you reach the point where enemies can no longer kill you with one attack, the difficulty drops off a cliff again. If the first 2-3 levels out of 15 in a stage are impossible, then you could watch TV while mashing the attack button and still make it through the rest. Boss fights are always over in a couple of hits if you are of high enough level, which is guaranteed if you managed to make it through the hordes of fodder in its respective stage.
The game is not totally bad though. One idea that showed some promise was the use of gem collecting. In the game the hero finds many small magical gems that can be fitted into a "gemframe" that he carries. This can bestow many useful properties such as greater attack power, additional attacks, or more powerful magic depending on the type of gem used.
In the end the game solidly nails the mechanics of an action-RPG, however it suffers from a huge lack of depth and variety. The only difference between each stage is its appearance. All levels in all stages use similar map layouts that aren't especially large and take minimal time and effort to navigate. Furthermore, for a game on the DS, it implements NO touchscreen features except menu navigation which may be a disappointment to many fans.