Using shortcode is working perfectly thanks to s2Member.
The only problem is that admin himself can not access all content but only the public one. I hope that this kind of capabilities will be solved in the future to be able to link member levels to existing user capabilities in Wordspress, like: level1=contributer, lever2=author, levels 3-4 authors+cutom capabilities, etc.
However, I solved it like the following:
[s2If current_user_is(s2member_Level 4) OR current_user_is(administrator)]
Some premium content for Level 4 Members.
[/s2If]
[s2If current_user_is(s2member_Level 3) OR current_user_is(administrator)]
Some premium content for Level 3 Members.
[/s2If]
[s2If current_user_is(s2member_Level 2) OR current_user_is(administrator)]
Some premium content for Level 2 Members.
[/s2If]
[s2If current_user_is(s2member_Level 1) OR current_user_is(administrator)]
Some premium content for Level 1 Members.
[/s2If]
[s2If current_user_is(s2member_Level 0) OR current_user_is(subscriber)]
Some content for Free Subscribers.
[/s2If]
[s2If !current_user_can(access_s2member_Free)]
Some public content.
[/s2If]