Sadly with 1GB it'll just crash and burn.
The game eats VRAM like no one's business. It actually seems that the game might have a small memory leak as the game can become a horrible stuttery mess even on graphics cards like the GTX 980 or AMD Fury X which have 4GB GDDR5 and HBM 4GB respectively.
I've seen people post numbers as high as 8GB of graphics memory being used.
That can only mean one thing: huge textures (well, and memory leak as well, indeed). I remember Shadow of Mordor for PC has an option for HD textures as well, but even this requires gpu with 6gb VRAM.