Pretty good idea and execution. although I would prefare if wandomized keys were shown at the start I can see you discovering them can be fun for some.
other than that, had a problem where down and right got assigned to "S" key so I couldn't move past some spikes. at fist I thoughI there is clever way around it but I guess it was a just a bug. and, of course, I realized I can just reset level after I already refreshed the page :)