REMARKABLE
Ran perfectly on my system.
SPECS: WIN10 / i5 6500 / GTX 1070 OC / 16GB RAM

FIRST RUN
I first ran every executable directly from the directory (not through itch.io client) and results were as follows:

1. DX11 - flawless
2. DX10 - minor stutters (room transitions)
3. OpenGL - minor stutters (throughout the benchmark)
4. Vulkan - stutters (throughout the benchmark)

SECOND RUN
I then ran every executable through the itch.io client, prompting me to install Microsoft Visual C++ (which failed every time) and results were as follows:

1. DX11 - flawless
2. DX10 - flawless
3. OpenGL - flawless (unnoticable dips in fps)
4. Vulkan - flawless (unnoticable dips in fps)

One thing to note is that there were slight differences in fps by executable as follows (highest fps - lowest fps):

DX11 - DX10 - OpenGL - Vulkan

*The latter two being almost identical on the SECOND RUN.

I also sent the results in after every execution.