It does not gain any more EXP points and has max happiness unless it was caught at level 100.
Nothing special.
Then you have a level 70 pokemon!
Drifllon evolves when it reaches level 28.
You level it up until it reaches level 40. It should then evolve into a Rapidash.
Gastly evolves into Haunter once it reaches level 25 or higher.
Nothing really, only the fact that you have it, and it exists.
Gastly evolves once it reaches level 18. It evolves into a Haunter. To evolve Haunter into a Gengar, you must trade it to another player.
Luxio evolves into Luxray exactly at level 30 on Pokemon platinum.
you need to get max happiness then it will evolve. this usually happens around level 18
it can't go any higher so it's a really good Pokemon (depending on the trainer of course)
at level 34
Level 100
level 30