Azumarill doesn't evolve according to level in Pokémon HeartGold because it's not capable of evolving at all.
Evolve Marill @ level 18.
it doesn't the stages are azurill marill azumarill
Marill evolves into Azumarill at level 18.
Marill evolves into azumarill at level 18
Marill evolves into Azumarill at level 18.
Marill evolves into Azumarill at Lv 18.
sentret evolves at level 20 in Pokemon heartgold
Azumarill, and none of its unevolved forms, can lern Ice Beam through level up, however, they all can learn it through a TM, depending on which version you're playing. In Diamond, Pearl, Platinum, HeartGold, and SoulSilver, it's TM13, which can be bought at the Veilstone Game Corner (Diamond, Pearl, Platinum), or Goldenrod Game Corner (HeartGold, SoulSilver) for a massive 10000 coins.
Ampharos does not evolve in Pokémon HeartGold.
Level 36
Level 15.
level 30