Roblox:

Is available to play on Xbox, PC, Mac, and mobile, so if you have any of these you can get started, for free!, But need networking all games are online, it‘s free without download or purchase in games but clothes and new customs and something you must buy it, but you can play any game for free

Flash: No need

But need networking all games are online, it‘s free without download or purchase in games but clothes and new customs and something you must buy it, but you can play any game for free

Roblox is free-to-play, with in-game purchases available through a virtual currency called "Robux". As of August 2020, Roblox had over 164 million monthly active users.

Here are the Roblox System Requirements (Minimum)

• CPU: Roblox recommends you have a recent processor (2005+) with a clock speed of 1.6 Ghz or better. ...

• CPU SPEED: 1.6 GHz.

• RAM: 1 GB.

• OS: Roblox will install on Windows 7, Windows 8/8.1, or Windows 10. ...

• VIDEO CARD: Roblox requires DirectX 9 minimum and Shader Model 2.0.

• Pros: 1.1 1. Available For All Devices. 1.2 2. Encourages Creativity. 1.3 3. Recover Lost Account. 1.4 4. Parental Control. 1.5 5. Make Real Money.

• Con: 2.1 1. No Account Deletion. 2.2 2. Special Privilege To Builders Club Members. 2.3 3