Your idea of shrinking a metroidvania to one screen feels amazing. I usually dislike to backtrack and seek out secrets on the typically vast maps of this genre, so for me it was like a refreshment. Due to its limited scope, the backtracking never felt tedious and I was more encouraged to look out for the secret gems.
From negatives I can only point out that with every death my character became more and more hidden in the textures. Nonetheless, it is a small technical problem that, I am sure, you will be able to fix.