okay, played some more black mesa:

there's a bunch of stuff they redesigned really well - for example, in the original there's a short section with a maze of vents that you have to find your way through, and it was always frustrating and confusing.

in black mesa, there's just 1 vent and it takes you straight to the next area.

a lot of other areas have been redesigned to make more sense... let me actually make a comparison picture real quick...