You had difficulties, still you could have done it better.
still为副词，前面为逗号的前提下，可以这样用吗？
可以。 still 的含义是“虽然如此仍然”、“但是还”。如：
His stomachache grew worse, still he didn't complain. 他的胃越来越痛，但他还是没有抱怨。
