I'm a developer around a day job too so I know exactly what you mean! I did a game jam a few months back that I pushed myself to make all the models by hand and learned a LOT from doing it. I still prefer to spend my time with the logic side of things. haha. You did a fantastic job and just to be clear, I wasn't mentioning the pre-made assets as a negative, more a positive that you used them seamlessly! It wasn't like you used the demonstration level and just threw a few things into it, you actually built the game just as a developer with an art team would. Games like this just make me love using UE4 even more!! =)