Yes, you can. Pokemon HeartGold uses the time from your DS settings. So, change the time on the DS and the time in Pokemon HeartGold will change with it.
nothing.
oddish you have to get him at night time
you cant do that.
There is no best Pokemon on Pokemon HeartGold.
there is no Pokemon Mansion in Heartgold.
no sorry...
They are not in Pokemon HeartGold
u have to change your ds time and date then your Pokemon games time and date will be the same
where is the pokemon transfer lab in heartgold
you can't face him a third time
Not for a very long time.