Unhappy [Q] Data restore from nandroid backup?

So, today I turned my phone off because I had a class and it didn't turn on again.
Everything worked properly yesterday before switching to ART, so I think that ART caused my bootloop.
I've tried everything I could (without wiping anything), but it still didn't boot properly
I made a nandroid now, and I clean flashed a new ROM
It's not the bootloop that bothers me, but the fact that I don't have a recent backup of the only game I play
So here's my question: is there a way to switch back to dalvik without actually doing it from Developer Settings? Some kind of adb command maybe?
If not, how can I restore app's data from my nandroid? I've tried both Titanium Backup and Nandroid Manager, but the app force closes when I try to open it

GApps: PA stock package
Kernel: ALKKX and the one that comes with ShinyROM (didn't boot with both of them)

I don't think that it can help but the game is Geometry Dash
I was like #20 in the global score with more than 1k stars, I don't want to start it over ughhh
Device: sᴧᴍsᴜɴɢ ɢᴀʟᴀxʏ sɪɪɪ ᴍɪɴɪ
Status: rooted
ROM: AOKP (Maclaw)
Kernel: Benz-Maclaw kernel
Theme: KLP/Holo Sense
Script(s): Crossbreeder
Tweaks/apps: Xposed Framework, AC!D, Greenify, Spirit FM