Here is the full list of all 24 Rugby Challenge achievements.
Win the Rugby 15 Competition
Win the Top 14 Competition
Win the ITM Cup Competition
Win the Quad Nations Competition
The ref calls one red card against you
Score a conversion on pro difficulty
Win 60% of lineouts in a match that aren't thrown by your team
Make a try-scoring run which starts within your own in-goal area
Maintain over 60% territory in a match
Get gold medals in every tutorial
Create and save a custom player
Win the World Championship Competition without losing or drawing a match
Do not concede more than 2 penalties in a single match
Maintain Over 60% possession in a match
Complete 25 online matches
Complete 50 online matches
Score 4 consecutive tries with Jonah Lomu vs England
Win 10 matches, each as a different team
Win a match with 2 players sent off
Break through a full back with Jonah Lomu
Complete Career Mode
Watch through the credits
Unlock 'Team Lomu'
Collect $100,000 Rugby Dollars