Just a simple or little writeup !!!!!
Decompilation long with a lot of folders, files, and others !!!!!!
Just use "unzip stress.apk -d stress"
As in all CTF with apk, the first thing to do is lookin at the folder /assets/ !!!! 
Just see in folders /stress/assets/bin/Data with file level0 !!!!
Just "strings level0 | grep flag{"
BINGO "flag{1_kn0w_ARCore}"
To sha256 ===> a621b0c77657bb1f80a843dba19521a0362905aac51a0b27e49b3fd2a1a13c61
This is the flag for 453 points: "a621b0c77657bb1f80a843dba19521a0362905aac51a0b27e49b3fd2a1a13c61"
Thanks and i'm sorry for the little writeup but no need for more for a little writeup !!!!!