I like the composition a lot, lots of really cool ideas and nice melodies. The choice of instruments really helps sell the setting and the characters, and the stylistic roots distinguish it from a lot of game OSTs. Love the time changes in Un Paso and the story they tell.
One thing that I think would make these pieces stronger is more dynamic range, within each part as well as the overall mix. Your orchestration lends itself to dynamic playing that could really enhance your compositions. For instance, when the bandoneon comes in in the main theme, it stays at a pretty consistent volume, and seems to fill as much space as the entire string section, almost like someone's playing the higher stops on a pipe organ. Having it come in quieter with the strings coming down to meet it, giving it room to swell and fade, could highlight its distinctive voice and make the piece feel more like a live performance.
I agree with previous comments that the piano sticks out a little, especially on Un Paso, but I'd say more dynamic movement in the line would probably go further than a different sample set. More contrast between the grander and more intimate moments would also make the storytelling even stronger in both pieces.
Criticism is easier to elaborate on than praise, but I think there's more to praise than to criticize. Awesome work!