Technically, the ! part in’t necessary, but a lot of people use it for names. What the ! actually does is capitalize the first letter of the word, so if you wrote your name as “bob” and you use ${Name}, it will show up as “bob”, but if you use $!{Name}, it will show up as “Bob”. However, if the name was already spelled with a capital letter, it will look the same whether you use ${Name} or $!{Name}.
Edit:… Well, this is weird. Why isn’t the dollar sign showing up when I type it? 
thanks:) I won’t use ! just in case the player wants an all lowercase name.
Quicktest can be a bit quirky with its error messages and sometimes misses things you’d expect it to catch and it sometimes seems to bark at shadows but you should be able to write your game in a way that keeps it happy. There could well be things in there that will cause your game to break that you’re not seeing because you’re writing it and you know the ‘right’ way to run through your choices. That’s why people usually ask others to ‘test’ their games for them.