A mobile browser game can feel just like a native app by supporting portrait...

https://smart-wiki.win/index.php/How_Do_I_Make_an_HTML5_Game_Feel_Like_a_Native_App_on_iPhone%3F

A mobile browser game can feel just like a native app by supporting portrait mode for easy one-handed play, using caching to load quickly even on slower connections, and offering touch-friendly controls that respond smoothly