Here is the full list of all 32 Millennium 2 - there are Take Me Higher achievements.
Kill Gigantine
Kill Queen Twin
Spend 20+ hours on the game
Kill Lion King
Kill Ooze King
Repair Gravitron
Complete 8+ quests for Dee
Pass Gigantine's Lair
Tame 30+ Enemies with Jezabel
Kill 50+ enemies with Abu
Complete 6+ quests
50+ items found
Find 5+ secret rooms
Complete 1 quest
Create Your Government List
Find 1+ secret room
Finish the game in less than 9 hours in Hard Mode
Held more than 30 000 Gold
Kill Trickster King
Kill 1+ enemy with Piu-Piu
Kill 50+ Enemies with Gravitron's Laser
Kill 200+ Enemies with Abu
All quests completed
All secret rooms found
Play 1+ hour
Complete the game fully (all quests, secret rooms and animal kings)
Hard Mode Completed
Kill all animal kings
Kill Zombie King
Kill Scorpion King
Kill Gorilla King
Kill Imp King