It was a VERY brave move to try and get such a huge level for a jam entry. It shows how you run out of time. Also 2min, 28 second before deadline submittion. That is a pretty close one!
It always better to create a small level first, polish mechanics and then add beef on top of foundation you already have. That way your time will be spend much more efficient. At the very least you will be able to make more fluid basic combat/interaction.
Keep working on projects! Its a very good practice and quite fun at the end! :)