Here is the full list of all 21 BlazeRush achievements.
Kill the opponent with each weapon but the slime
Die a hundred times
Spend 2 seconds in the air
Do a NO SCOPE, while doing a 360
Drop a slime while in the lead
Break the sound barrier
Join an online party
Rise from the last spot 5 seconds before the finish
Complete your first serious competition
Be the leader and lose it all 5 seconds before the finish
Overtake the leader a second before the finish
Be the king for most of the race
Hit yourself with every possible weapon
Win in each of the three modes
Destroy 50 cars with the autogun
Destroy 40 cars with the saw
Destroy 30 cars with the missile
Destroy 20 cars with a soundwave
Unlock all cars in career
Defeat the boss
Complete all career missions