Good call here, only really want to compare the micro versions, with foot note on console versions, of original Contra.
Played a lot of the C64 version, back in the day, blocky sprites, washed out colour scheme (and having to press SPACEBAR to jump was bloody annoying), but loved the games speed and music.
Have tried the CPC version via emulation, most colourful, if a little messy, but lack of in-game music kills lot of the 'feel' of the game i find.
Speccy version, nice sprite definition, great music (even if it struggles at times), good sound FX, apart from your gun firing.Impressive, as is...
The GB version, though my hatred for the GB screen meant i never played it on the GB.
Find myself playing the Nes version (via emulation), a lot these days, dunno why, just are.
Nice to see Mass Effect 2 designers a fan of SNES Super Contra, as last boss a blatant rip-off off 1 found in the game.