There are many Naruto web games around, but only the one in China under Tencent Games is officially licensed by its Japan counterpart. A co-development effort with Namco Bandai and CyberConnect2 (developer of the Naruto console games), the story starts right from the beginning.
Playing as a member of Team 7 initially, players will soon be able to mix different characters acquired via the cash shop (random draw), quests or from daily login rewards. It is basically the same system as the numerous random character gashapon found in mobile card games these days.
The most interesting part about the whole game is figuring out which characters will sync better in terms of combos. Combo skills are automatically activated when the requirement is met, and not all characters will be able to do so. This will trigger a chain effect, and even a round 1 kill at times.
Combat is semi-boring, with auto-attack enabled. Of course, this system is not perfect, and for some combinations, it is better for players to manually activate the special skills. Chakra (or MP) is needed to trigger the skills, with each round getting more max chakra until maxing at 100.
Typical of an Asian web game, there are various PvE and PvP modes along with several other features. There are plenty of money sinks, which no doubt are all money makers. An example are the gems found in the cash shop, which directly strengthens characters in battle.
Since Tencent Games probably licensed the IP for tons of money, I doubt we will see an overseas version. It seems like a waste not to pursue a full-fledge client MMORPG, as the foundation is there to make something special. Come to think of it, the Naruto manga ends next month.