The biggest thing that makes C&C what it is is called the SEIGE Engine and 5E doesn't use it. The SE is used in task resolution and you basically decide which ability scores are your "Prime" or primary ability scores. Your first one is determined by what class you chose, Fighter = Strengths for example. Non-Humans choose one more ability and Humans get two more for a total of three.
Also C&C does NOT use feats.
There are also several other smaller things where C&C is not like 1e or 3e. I suspect it was to avoid copyright issues, such as initiative and encumbrance.
As mentioned earlier one of the best things about it is that you can use just about anything from 0E to 3E with very simple conversion. It's very easy to convert "on the fly".
The other thing I like about it is that it is so easy to house-rule. The sub-systems in it are fairly simple so it's easy to tinker.
Also C&C does NOT use feats.
There are also several other smaller things where C&C is not like 1e or 3e. I suspect it was to avoid copyright issues, such as initiative and encumbrance.
As mentioned earlier one of the best things about it is that you can use just about anything from 0E to 3E with very simple conversion. It's very easy to convert "on the fly".
The other thing I like about it is that it is so easy to house-rule. The sub-systems in it are fairly simple so it's easy to tinker.