Yes, it's true - your phone is lying to you! :) Everything should work fine even with 1GB of RAM or less.
During the design process, we've decided to choose min. platform version 4.1 requires at least 1 GB of ram but our test devices had only 512 MB so everything worked well without any problems... Till now.
But in the latest update Unity 3d engine updated to 5+ which means developers need at least 2GB of ram to be able to run this game smoothly in high settings.
So if your device has some less - as mentioned before - it should still work, but not as good as with 2 or more GB of RAM.