Your location says UK- so I suppose you'd like to compare to the A'Level system (unless you are Scottish).
The main difference is that in the UK students choose 4 subjects only for year 12, and the choice is almost endless, and then drop one and concentrate on 3 subjects for A'Levels (exceptional students are allowed to keep up with 4, but this is rare). In the UK, students can drop all the classical subjects if they wish- and can even stop doing English, maths, a language, history, geography, etc, if they so wish. A student can for isntance study, say, art, music, design and IT- or, as another example at the 'other end' of the scale, maths, further maths, physics and chemistry.
This system is unique in Europe, and has real advantages and disadvantages. In Europe, and in Switzerland, students who choose to stay at school for the Bac/Maturité have to continue all subjects- but can specialise in some more than others. But they all have to continue to study 2 foreign languages + of course the national language of where they live, maths, sciences, history, geography, etc, and pass in all subjects to be admitted to Uni. It is therefore very difficult for a student who is not proficient in the national language of where they live to study at that level- as they have to study difficult texts in all subjects, write formal essays, be able to debate, etc.
In Switzerland students don't apply to Uni in the same way as in the UK via UCAS. If you pass the Bac/Matu, even with relatively low scores (4 out of 6 being the minimum in ALL SUBJECTS, around a C grade, you can go, and then they will 'weed' out during the first year. BTW if you fail one subject, you have to re-take the whole year and the whole exam, unlike the UK where you can just re-take the subject you failed. A friend's daugher failed by 1/4 of a point in maths, re did the year with extra tuition in maths, but when she did the exam the next year, she passed in maths but failed in German- and gave up.
Hope this helps. If it does not, perhaps you could ask specific questions so they can be adressed.