Here is the full list of all 24 Tunche: Arena achievements.
Beat Horde mode without having spent XP on the Skill Tree.
Access any of the Leaderboards.
Reach Wave 50 in Endless mode.
Get a total of 50 S, SS or SSS kills in Endless mode.
Use all the skills.
Defeat one enemy of each type.
Defeat 50 peccaries in total.
Defeat 30 trunks in total.
Defeat 10 giant frogs in total.
Defeat Boutu in Horde mode.
Complete a Wave in Endless mode.
Buy a skill in Endless mode.
Beat Horde mode without having chosen any reward.
Annoy the Skill Tree guy
Reach SSS combo style.
Defeat Boutu in Horde mode without being damaged.
Reach SS combo style.
Air juggle the frog plushie 5 times.
Defeat 75 monkeys in total.
Reach S combo style.
Defeat 200 frogs in total.
Clear a Wave without getting hit.
Choose a reward in Horde mode.