Just like how flowing water has no form and how the rustling wind is invisible, can ROBLOX take on any individual shape with every game one builds in it. You could make a birthing simulator, or a 15FPS FPS...
ROBLOX is a game that allows you to make games yourself; all you need is lua. Presumably. I believe the primary demographic is children, but JoJo fans and protogens like to play it, too. Not what I'd expect.
Over 3 billion accounts have been registered on ROBLOX (One third of them probably terminated), and the most popular games - called "Experiences" - on the platform tend to have a daily player count in the 10k range. Whether or not these games interest you depends on your tastes.
Of course, chances are most of the "experiences" on the front page won't interest you. Like, at all. So, uh, have fun?
Things you can do in ROBLOX:
Currently, no reviews are in the making. Sonic is dead.
I judge games not only by their quality, but also if they are fun to play. Thus, bad games that are fun get a better rating than games that bore me to death.
To developers of games I reviewed: These reviews are not meant to insult you. I am simply stating my opinion about your game. You might disagree with me and say your game is fine... And that's OK. You don't have to listen to me; as long as your players are happy with your game, you don't have to change the game. Just because I don't like it, doesn't mean no one likes it. Please don't take it to heart. I love you!