I tried adding dark spyro but it said the code didn't exist in the game yet.
Interesting...Which dark spyro did you put in the code for? It won't work if you put in series 2 dark spyro.
Actually, don't answer that! I found the problem! It will be fixed in the next Patch/Update! For now, type in normal spyros code and the game will give you the option to select it.
