Ah, I thought you meant people could only vote for a party, not individual MP. Yes, the largest party delivers the Prime Minister.
In America we have a primary system so you can vote for who the party candidate will be in the final election (this goes for almost all elective offices.) To my knowledge, I am not aware that such a thing exists in parliaments. Doesn't the party itself choose who the MP candidates will be? So in my mind, you really are voting for the party instead of the individual, as candidates are unlikely to be far off from party policy, whereas here you could potentially choose a republican to be the democratic nominee in a Congressional race. There are some pros and and cons to both systems, I guess it just depends on your preference.
In the Netherlands it depends per party how candidates are placed on the voting lists. Normally everybody who wants can sign up to be on the list for that party, the chair of the fraction is often number one on the list and other current MPs follow, new people are added after that. During voting you vote for a person, normally the first on the list. If the seat is in the vote overflows to the next person. However if someone gets more votes then the person in front of that person he/she gets the seat (even if the party doesn't like it). In that case there are 3 options: the person can keep the seat, the party asks the person to give the seat away and in that case the person can choose to do it or not, or the person decides to become an independent MP (this is also the case if the person is thrown out of the party).
After elections the largest party gets the initiative to form a coalition, where the number 1 becomes the Prime Minister and ideally you want to have more then 50% of the seats in the parliament, although that isn't required. Our current Cabinet contains 2 parties, supported by a 3rd. That in most cases give >50% support.
