[@Lou] Hi Lou!
Heimdal updates your most security-critical 3rd party applications, which are exploited in over 65% of attacks (some recent statistics say even 85% of attacks are delivered this way).
To answer your question, yes, Heimdal let’s you choose which software you want it to keep up-to-date. But deselecting some of them would mean leaving your computer vulnerable to attacks that exploit the vulnerabilities in those apps.