Is this supposed to be an expression, an idiom or a saying or proverb or whatever, because I have seen this used a lot. There seem to be no entries for "前進しか許す"
This video on youtube gives the translation for this sentence as: https://www.youtube.com/watch?v=quR5-FEaM9c&t=3m27s
私には前進しか許されないのだッ！ "I will never forgive them!"
But if you use google translate it gives: 私には前進しか許されない = I can only move forward