Do you know what core means? That is the
core of .NET framework[
^], it is not a gaming engine or a user-interface rendering tool for you. It contains the basic classes, namespaces and other stuff required for the .NET framework to run. Once the .NET is up and running you can port your applications and run them. If you go to GitHub and look for the desription, you will see,
Quote:
It includes System.Collections, System.IO, System.Xml and many other components.
If you want to write games or other 2D graphical applications, use an appropriate framework such as Unity 3D for gaming, WPF or Win Forms for user-interface application. .NET framework (and the core) would just power them up. All of other stuff is based on your own platform or framework; WPF, Unity, Win Forms, ASP.NET etc.
.NET Core runs .NET framework, what more bigger you want it to run for you?