Is there much crouch jumping like the original (crouching at the end of your jump to reach higher ledges)? When Black Mesa first released it ended before Gordon reached those areas as the team wanted to try and redesign them to flow better with the chapters that came before it the game is now launching with their new interpretation of Xen. Xen was a controversial (in terms of quality) set of chapters in the original Half Life that made some pretty significant changes to the moment-to-moment gameplay, the biggest of which was a focus on platforming.

Xen, as mentioned above, is significantly redesigned however.

No, parts of the game are reimagined though it does still aim to include a lot of the big “moments” from the original Half Life. It has been in Early Access for almost 5 years as the team worked to reimagine Xen and is now leaving Early Access for a full release. Black Mesa is a fan remake of the original Half Life in the Source Engine that was given the greenlight by Valve to be sold on Steam.