The a level is very different to the gcse, but I found it to be ultimately a lot more rewarding as well. Like most gcses, gcse physics is essentially just memorisation. At a level, you really have to understand the content, which can be quite tricky to get your head around at first. This is because questions focus more on the application of key concepts to a situation you may not have even come across before. The difficulty of the maths is also a step up, but the maths is easier than single maths a level, as long as you understand the physical ideas behind the maths.