There is a balancing issue; most of the dice are ineffective, relying on luck if chosen, but there are four types of dice that are actually useful:
The bear for offensive as it can fit into any slot (though incremental slots do not count—why?).
The hedgehog for defensive, as it can block at least one damage even if it cannot fit into any slot.
The frog and ram are for energy regeneration.
Some rare dice, like the wolf, highlight how this game contradicts itself. For instance, if you roll a wolf dice with a 1 and choose to wait for five rounds to accumulate 6, it is highly probable that you would not survive long enough for that to happen. It's better to roll a new dice to 6