The original idea was to make a full-fledged big soundtrack... but due to tight time constraints I decided it would be better to make more dynamic tracks that would be intense (as much as my limited musical experience allows), because the listeners would get bored listening to an already long soundtrack. Heh...
About the need for drums and percussion - I agree (The only problem was that I +- understood that it needed to be done and HOW to do it only on the very last day of the deadline, because during this difficult week I was discovering many new, but basic things in creating music)