Giving this almost full scores all round!
The introduction to the mechanic was nice and early and clearly a unique take. I loved that it worked as a dash, attack and key all in one. I was disappointed the second place to use it didn't also open a door - I felt the first use established that's what it did, but after that I got it and it was fine.
I loved that there were 'platforming' ways to get through but I could go faster with good use of the dash. The cape is an excellent touch. Enemies were simple but a nice challenge (I stopped playing at the first boss' second phase, the run back to it grew frustrating)
The grey pillars initially I wasn't sure if they were background or platforms.