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

https://delta-wiki.win/index.php/Why_Do_Some_Mobile_Browser_Games_Feel_%E2%80%9CUnfinished%E2%80%9D_Compared_to_Desktop%3F

A mobile browser game can feel just like a native app by supporting portrait mode, so it fits your phone screen naturally. It loads quickly thanks to smart caching, letting you jump in without waiting