This Game Boy version of Street Fighter II, marked as 'Rev A', is an updated release by Capcom. The 'Rev A' designation typically points towards a later revision that addresses any bugs or glitches found in the original release. The core gameplay of selecting a character and battling opponents remains, but there may be improvements in stability and potentially minor gameplay tweaks. 

Street Fighter II (USA, Europe) (Rev A)

Stargate (USA, Europe)