Simple. All you have to do is catch every single last Pokemon in your game even, if their an event Pokemon that way to long over.
Or you can use action replay to fill it up.
Or you could ask some of your friends to trade with you so you can get the information you need then give them back their Pokemon.
Or you can cheat to get all of the Pokemon there.
If you find all of these too complicated, you simply see all the Pokemon instead, but if you do, your pokedex will have little bits and pieces out of it (such as cries, weight, size, ect.).
There is no way you have to compleate the pokedex but most of it is at the gyms.
You have to have seen or caught every Pokemon in the game
you can simply all you have to do is compleate the heon pokedex then go 2 pro birch and he'll give you a choice of totadile chicorita or cyndiquil
i am passed 12th or i want to compleate my graduation so how can?
darkrai i think. You can get darkrai at a Nintendo special event or by using a cheat which i don't know. P.S. I've got a darkrai, by Nintendo event!
your almost finished the game! after you beat heatran, you got to compleate the national pokedex. after that, battle every trainer in the region. after, get 6 Pokemon level 100. then you beat the game!!!
Well in simple terms all you need to do is defeat the elite four...but in another sense oak did set you out to complete the pokedex as well but the credits appear after the elite four, not quite sure after completing the pokedex (Just a word of advice, don't use cheats, they ruin the game and mess it up)
you fight the places and keep winning then beet the battel brains and get medals also compleate the sinno pokedex and u can get to the survival area and the resort area there is lots of things to do just explore like i am.
you compleate everthing like i did
Yes, 'No.' is a compleate sentance.
compleate missons.
it is impossible to compleate poptropica but you can win a meddal in every world but sence poptropica keeps growing its im possible to ever compleate the game. hope that helped