Here is the full list of all 29 Riptide GP2 achievements.
Upgrade a Hydrojet.
Paint your Hydro Jet.
Place 1st in any event.
Get 1 star in all Career events.
Get 2 stars in all Career events.
Get 3 stars in all Career events.
Earn 3 stars in every Hot Lap.
Earn 3 stars in every Freestyle event.
Earn 3 stars in every Elimination event.
Earn 3 stars in every Race event.
Get 1000 points in a Freestyle event.
Get 1500 points in a Freestyle event.
Get 2000 points in a Freestyle event.
Buy 1 Hydrojet.
Buy 4 Hydrojets.
Buy 8 Hydrojets.
Upgrade a Hydrojet fully.
Play an Online match.
Win an Online match.
Win 50 Online matches.
Win 100 Online matches.
Win a race without the rider.
Find the hidden easter egg.
Win an Online race event by less than a tenth of a second.
Lose an Online race event by less than a tenth of a second.
Jump over 200 meters.
Unlock a level 10 Stunt.
Reach level 20.
Smash a bridge in the Factory Shift event.