Merciless
Else clues• Awfully cruel
• Beastly
• Cruel, very dry Pacino
• Exhausting
• Hard to endure
• Harsh
• Harsh-plus
• Inhuman
• Inhumanly cruel
• Like a Buffalo winter, per reputation
• Monstrous
• Painful, as honesty
• Pulling no punches
• Punishingly difficult
• Really, really tough
• Savage
• Taxing
• Tough
• Truly rough, as a test
• Unrelenting
• Very harsh
• Vicious