The question is, does "low memory" mean low RAM or low storage? The 1GB free will be storage, because the Iconia B1 only has 0.5 GB of RAM according to the specs I've seen. So if you've already installed the game but can't run it, it is probably RAM (unless perchance the game wants to download a huge amount of data before it first runs).
If it's RAM, all I can suggest is closing as many apps as you can before running the game.
Otherwise could you post again with more information, such as what the game is, what system software version you are running, whether you've ever run the game successfully and whether any other apps are affected?