I had this same problem and I found a solution!
Basically changing the anti-aliasing setting from the default version messes something up and you can't open the game after changing it.
I typed in %LocalAppData%\Packages\Microsoft.MinecraftUWP_8wekyb3d8bbwe\LocalState\games\com.mojang\minecraftpe into the Windows search. Then I opened the options text document. I changed the gfx_msaa:1 into gfx_msaa:4 (making the anti-aliasing setting back to default) then saved the document and closed it. After that my Minecraft loaded properly!
UPDATE: I found a solution!
Basically changing the anti-aliasing setting from the default version messes something up and you can't open the game after changing it.
I typed in %LocalAppData%\Packages\Microsoft.MinecraftUWP_8wekyb3d8bbwe\LocalState\games\com.mojang\minecraftpe into the Windows search. Then I opened the options text document. I changed the gfx_msaa:1 into gfx_msaa:4 (making the anti-aliasing setting back to default) then saved the document and closed it. After that my Minecraft loaded properly!