Here is the full list of all 50 3 Stars of Destiny achievements.
Find 10+ secret rooms
Kill Uzair
Surprise 10+ times the enemies
Mend Sarah's leg
Find 90+ items
Kill 100+ enemies
Kill 200+ enemies
Use XP Pumpkin
Walk 10000+ steps
Find that secret room with a cool sword in
Find Sarah again
Play 1+ hour
Find Sarah
Kill 10+ enemies
Hold 5000+ gold
Walk 1000+ steps
Hold 100+ gold
Find 6+ items
Finish the game in less than 25 hours
Spend 80+ hours on the game
Held more than 200,000 gold
Held more than 900,000 gold
Go through 3000+ fights
Kill 3000+ enemies
Kill 1000+ enemies
Kill 150+ enemies
Kill 300+ enemies with spells only
Kill 50+ enemies with weapons only
Kiss Sarah
Hit 200+ times on the punching machine in the village
Hit 250+ times on the punching machine in the village
Use 20+ XP Pumpkins
Find 40+ secret rooms
Kill Golden Scorpion 10+ times
Walk 100000+ steps
Hold 100,000+ gold
Save 100+ times
Find 700+ items
Complete 30+ quests
Finish the game in the hardest mode
Use Guanidia's Kamikaze 100+ times
Use 1 Ocean Love
Find all 51 secret rooms
Make Luciana and Herasia "friends".
Use Egress 25+ times
80+ bonus crystals used
Change Spark's strategy 19+ times
Win Colyseum
Find all relics
Find all artifacts