How I understood I need server for this
No, the web-browser release is a standard HTML web-application, it can be either hosted on a web-server or run locally like most other HTML files can.
The ZIP files without a operating system abbreviation in their file-names found on the project's Downloads page are a local run-able copy of the release hosted on the Twine website. This is how I generally run Twine 2 when I am either testing other people code or designing solutions to questions, as I don't like the screen size and font size issues of the install-able release.
Can I increase scale of offline Twine?
I don't know of either a reliable method or a persist-able method of changing the scale of the install-able release, short of modifying the application's original source code and re-building my own personal version of the application.
Maybe someone more experienced with nw.js (node-webkit) based applications will have a solution for you.