The original intention was to release a PowerPC edition of NT 3.5, but according to Microsoft's David Thompson, "we basically sat around for 9 months fixing bugs while we waited for IBM to finish the Power PC hardware".

New features introduced in Windows NT 3.51 include PCMCIA support, NTFS file compression,[4] replaceable WinLogon (GINA), 3D support in OpenGL, persistent IP routes when using TCP/IP, automatic display of textual descriptions when the mouse pointer was placed on toolbar buttons ("tooltips") and support for Windows 95 common controls.

Web browsers based on and including Firefox were operable up to version 2.0.0.22, released in April 2009; they required a few manual file updates to work without compromising browsing security.

The preview program provided early feedback for the Shell Update Release, the next major Windows NT version with the new interface built-in, which was released in July 1996 as Windows NT 4.0.

Five Service Packs were released for NT 3.51, introducing both bug fixes and new features.