Where the Wild Things Are
49 Achievements
12-15h
Demolitionist
Defeat five Fireflies with one bomb
47.9%
How to unlock the Demolitionist achievement in Where the Wild Things Are - Definitive Guide
Uber Old Acc
TrueAchievements
TrueAchievements
This one is a tad bit annoying but an easy place to obtain it is on the level called "Rebellion". Once you make your way around the first part of the game where you are getting dirt clods thrown at you by the Wild Things you will enter your first cave. In the cave you can find a ton of firefly hives. Walk to the one in the back an the instant explode firefly will appear wait for them to pile around then hit the instant exploder and the achievement will unlock.
OnceFallen
There are many places to get this, but the first place where you meet the fireflies that have bombs is probably one of the easiest since there are 2 bomb dropping firefly nests and two regular ones in the area to respawn them if you dont' get it the first time. All you have to do is beat a large (bomb) firefly so it drops it's bomb, run around to attract more fireflies and run back by the bomb so they surround you and get blasted when it explodes. It took me 2-3 tries to get 5 before the bomb exploded as some few away just before it went off, but keep trying and it will come. There is also many other locations with large fireflies and multiple hives around as well, so take your pick of locations to get at.