Yeah, I can see why this chapter got cut from the game.
the arenas suck ass and are just no fun it fight in.

Very little enemy variety too. it's like 90% just HECU grunts.

Also for the majority of the demo you only really have the MP5 with very little ammo supplied and hand-grenades. Half-Life's grenades notoriously suck so being having to use them as your primary weapon is nightmarish.

While it is kinda neat as a piece of Half-Life history, it has no value beyond that.
This getting scrapped from the final game was for the better.