Here is the full list of all 19 Red Risk achievements.
Reach level 6.
Reach level 7.
Reach level 8.
Kill 1000 Infected.
Reach level 2.
Kill 100 Infected.
Survive your first tournament.
Enter the arena.
Reach level 3.
Reach level 4.
Reach level 5.
Survive five tournaments.
Survive ten tournaments.
Reach level 9.
Reach level 10.
Stay alive for 1000 seconds.
Stay alive for 2500 seconds.
Stay alive for 5000 seconds.
Kill 2500 Infected.