The first PC game to feature smooth scrolling platform gameplay in all directions is Commander Keen in Invasion of the Vorticons (Apogee/id Software, 1990). While home consoles such as the NES and SEGA Master System were designed with gaming in mind, PCs did not have the necessary graphical capability to deal with fully scrolling levels, as evidenced with the ''block scrolling'' of games such as Dangerous Dave (Softlink, 1988) and the non-vertical scrolling of Captain Comic (Michael Denio, 1990).
Please note: Comments below may relate to previous holders of this record.