On XFCE, the panel buttons now look Windows 95-ish, while using the original version from Redmond-Themes the panel buttons looked okay.

Redmond-Themes master:

Current master:

On the other hand, it seems as of current master some layouts have been improved, and some menu buttons now have a hovering effect (using Thunar's back/forward buttons for example). Looking carefully, it appears the hovering effect's transitioning state looked similar to Windows 95's buttons, so not sure if this might be related to the button's appearance on the panel.

EDIT: Also, maybe related to the changes, the button edges are less rounded than before.

OS: Manjaro Cinnamon (latest)
Monitor: 3840x2160 with HiDPI Enabled
(NOTE: It's possible some issues I'm having only happens with HiDPI enabled)

As of most recent commits it's working good so far, with some issues:

1. The panel is set to a transparent background with black text, which may not cope well with a dark wallpaper, although this can be customized through editing cinnamon.css to match my need.
2. A black line appears on some windows that weren't maximized (using Nemo for example). When maximized the black line disappears. Also, it seems on such windows, the titlebar color is the same when the window is active or is inactive.
   
   

The issues are mostly about Cinnamon, although the experience has been improved to a point that's good enough since moving out of the original Redmond-Themes repository. I also have a system running this theme but on XFCE and without HiDPI, and the experience there is near perfect for the time being.