at least I think its called the experimental phase, its when you made a game and publish it, but it isn't playable on roblox.
If your account is under 13 in age, you cannot play games in Experimental Mode (EM).
EM is a 'new system' to coincide with Filtering Enabled (FE). Games with FE disabled are considered to be 'experimental' and unsafe, as FE stops the majority of exploits people have access to.
So, to disable Em, you enable FE. There are two ways to do this (if I understand correctly):
A) Go into the explorer section in ROBLOX Studio, select Workspace, and in its properties, enable FE.
B) Go into ROBLOX Studio, and in the section at the top, select game options. Disable EM.
Okay, this is a frequent question. Here is how to get your game out of Experimental Mode...
Firstly, go to your Develop page and edit your game... Then, check th mark on the Filtering Enabled property (its the Workspace's Property)
Secondly, make your game active (playable) Then, go to the game's page and play it! Once a new server has started, your game is now out of Experimental Mode!
Have fun! :D