These are the recommended levels for the dungeons and the bosses in denpa men 2. Here is the list:
Mountain Cave: 3
3 ooks: 4
Feeding Grounds: 8
King ook: level 8
Ocean Tunnel: 13
Hammer Angler: 14-15
Digitoll Cave: 15
Wolfbear: 17
Tower Of Evil: 20
King of Evil: 22
Ocean: 24
Pyramid: 27
Mummox: 30
Grand Volcano: 35
Pawn: 38
Southern Dark Ocean: 40
Water temple: 45
Sepia Knight: 48
Afairyca/ Northern Dark Ocean: 50
Lady Viper: 55
Ice Island: 57
Ice Demon: 60
Evil Cave: 65
King Musher: 66
Ifrit: 67
Demon: 68
Ice Golem: 69
Holy Dragon: 70
Evil Witch: 55-85
Inferno: 60+
Demon Queen: 75+
Rook, Queen, King: 99
True Pawn: 55
Ultra Pawn: 65
Divine Pawn: 80
Octopaladin: 60
Master Oink: 70