A room consists of multiple tables. Each room has its own board design and sound effects, which will appear on all the tables that belong to it. The only difference between the tables is the bet amounts, number of doubles, and seconds per move.
When you complete all the tables in a certain room, you unlock the next room as well as a new board design and sound effects.
Here are the different rooms in order of advancement:
Rookie
Advanced
Competitor
Pro
Master
Legend