It seems that Ditto doesn't work as it was intended in the original Pokemon games. If it gets hit by any kind of attack (except ghost type) it's like multiplied by 10 intead of 1. And in the wild Ditto should remain immune ghost attacks.

And why can't I capture every pokemon? Like 20-30 pokemon cannot be found anywhere.

But anyway the game is fun. At first it's hard but the gyms are easily exploited for quick lvl up. But can we get less 0 rolls for exploring?