SpaceX launches towering Starship rocket in first attempt to reach space
cnbc.com
cnbc.com
Stage separation is a tricky problem. So is the problem of getting the fuel and oxidizer to flow through the complex network of pipes to feed all those engines and they succeeded at that.
https://www.youtube.com/watch?v=xdxzMPi19sU
I'd contrast that to solid fuel sounding rockets which are "just gone" after they ignite.