Can i make a game that has more gamemode in it?

Something like Roblox .
I want to make that when a Player opens my game
that than a window pops out and The the player can shoose out the levels i have Made.
Can i make this ?

Thank in advance.

Yes, by asset registry i should be possible

The main documentation explains C++ part of it, but there blueprint exposed APIs that let you use this in blueprints

Alternatively you can have hard coded list wither by having array with list of levels in defaults or some DataTable

If you talking about multiple GameMode, yes you can have multiple number of thems it even recommended if you have multiple game modes to have them as separate classes, not packing everything in single class. What you selecting in Project Settings is just default game mode.

UE4 got URL system that controls how game level is loaded and can have multiple options, the game sets which game mode will be used, so you can have level that supports multiple game modes (like in Unreal Tournament), read about it here: OpenLevel with options.... - Blueprint - Epic Developer Community Forums