Reducing Large Size of Published Files

Hi, I am facing a file size issue for the Storyline 3 output. My Project is having total 7 modules with separate assessment and the course is customized one. There are page level backgrounds and graphics. Also the Menu, Glossary, Help and Resource sections are customized, including the next and back buttons. The file size is going approx 30 MB for each module. The first module is 52 MB as it have one video. 

We have used the variables to control the Menu buttons which shows; Normal, current and visited status of each module. There are interactive slides in every module.

The knowledge check pages are having variables as there is requirement from client to restrict user. Like they cant reattempt the knowledge check page and it need to show the user selected options with tick and cross marks. We have used the survey templates and customized the design and functionality as per client requirement.

The problem is now the client requirement is to have all the modules as one course and the size is going more than 250 MB.

Can anyone help me on how we can reduce the final output size. Also what is the best way to use the background or images used in slides so that the size is reduced to maximum. Is it better to use the shapes instead of buttons for interactive slides and knowledge check pages like by converting  them into freefrom question?