Machinima put this up last week, following the Castlevania and Mario reconstructions in Half-Life 2. Anyone who's ever played Contra - that should be all of us, right? - will want to watch this start to finish. More than once.
Pretty shrewd how the level's creator (M0rtanius) staggered the platforms so you could shoot up foes above and below you, just like in the 2D version. But I'm guessing this isn't one-hit-kill difficulty.
Thanks Awwal for sending the tip. Sorry we spotted it so late.
Half Contra (Contra NES Remade in Half-Life 2) [Machinima on YouTube]