Running your apps in standard GL is all fine and good, but honestly, any time you're working deep in the graphic stuff and targeting mobile devices you're going to want your dev environment to mimic the real thing as closely as possible.
For windows, this means installing some kind of GL ES library. I think you've got a few choices, but here is how to setup the PowerVR ones. If it works with this, it's likely to work with iPhone, webOS, and Android devices too.
Next, we'll copy a piece out of the newly installed powerVR stuff into the Proton shared dir. Why do I do it this way? It's so my internal full backups will just “work” out of the box without needing to set anything up. I don't include them with Proton for legal reasons.
Clean solution, then build and run. You should see something like this: