I see no Flatgrass or Construct map selection button in the map menu.

I only see Bigcity in the sandbox category. Any suggestions?

Could you explain your matter more briefly, such as, SinglePlayer, or multiplayer? Are you using ULX in Multiplayer to change maps?

Otherwise it could be something with the gamemode’s .txt file, it needs to have ^gm in it.

Check if the maps are in the maps folder.

It’s on SP and the maps aren’t in the maps folder D:

Well, if the maps aren’t in the maps folder, they’re not going to be on your Garry’s Mod either. You’ll need to download them again.

Anybody got a mirror or mediafire thingy of the two?

Use this one.

The GMod 13 versions of each maps are more good-looking.

Try verifying your Garry’s Mod files.

Good idea!

[editline]12th October 2013[/editline]

It worked! Thanks a lot, everyone!