The HCS store is an organized and centralized GUI to install apps using the CLI tool (Command Line Install → how to CLI);
So the actual apps are not in the store.
Many apps, like the HOOP app, have published the source, at like, Github or Bitbucket, and can be downloaded and installed. But you have to search them yourself.
The HOOP app is available from Arie’s Bitbucket repository (https://bitbucket.org/QlusterIT/workspace/repositories)