Denodo Express is a free version of Denodo Platform. Whereas, the Denodo Platform 8.0 GA is a full version. Also, Denodo Express has some limitations compared to the full version of Denodo Platform.
For more details, you can refer to the [Limitations of the Denodo Express](https://community.denodo.com/docs/html/browse/latest/platform/installation/appendix/limitations_of_the_denodo_express_license/limitations_of_the_denodo_express_license) section of the Denodo Platform Installation Guide.
Hope this helps!