 Depending on the format it takes 10-1000 hours to crack a compression format. Then you have to spend the next 20 to write a working decompressor. Then you have to spend 20-100 hours to make a working compressor. To make a compressor that has a ratio near to the original, that&#39;s next 100 hours. Good luck.<br><br>Well, it&#39;s pretty fucking hard. Some are easier, some are harder, but it still takes time to get the general idea of the compression. When you know how it works, everything is simplier... <br><br>You could tell me what game and some offsets, I could look at it and see, maybe it&#39;s some easy one, or already cracked...<br><br>If that fails, try to learn assembly and bypass the compression (find where&#39;s the code that decompresses the data, change it so it just copies uncompressed data you insert to the ROM yourself) 