sorry...
I wanted to say the following before I head to bed
Mana and health need to be tied together so that they match the spiritual and physical aspects that make chakra. All jutus should should therefore be multiple of both the characters health and mana at the time when the jutsu was performed.
mana should not accumulate over time, or at least it shouldn't accumulate so fast. It makes the powerful characters too hard to beat, leading to super powered heroes taking over the game because no one can defeat them.
Rather have it that each player starts with 200 mana points. If a player kills any other player, then they gain that players mana making them essentially stronger.
Traps!
You need to have paper bombs and! AND the ability to disguise paper bombs and other traps, as valuable items. Using very little chakra a play should be able to make a trap look like an item, when someone comes to pick it up it EXPLODES! Killing a possible super powerful character.
Meaning that you killed someone stronger then you with tactic rather then strength adding an element of strategy to the game.
Levelling up!
In Naruto, when a character develops a new technique it often turn an ugly battle in their favour. I can only suggest that in your game when a character levels up, their health should be reset to full and that they do area effect damage to all surrounding enemies. This to create that element of gaining an advantage when leveling up, even if you are of a lover level them the team you fight.
I can implement these and other dears once you have given me the permission and perhaps a month in preparation.
I am currently swamped with work.
Thank you for the reply