The Big Evil Guy melody is soooo good! At 20 seconds the track really reaches its stride and I would love to hear this part of the track expanded and developed. You mention you have a lack of experience with DAW's but I think you've nailed the arranging and orchestration of these tracks even if its unfamiliar territory for you. When using reverbs I would NEARLY always use a 'Send' to an 'Auxillary'. You don't have to always do this for compositional choices but In my opinion, the reverb in "before the lair" had too much 'wet'. Otherwise, it's a fantastic OST, and I could see this being used in a game! But then it would exist? but it doesn't exist? but it should exist! Great work <3