Study buddy Bright Eyes here, helping you with your pony history homework. You’re welcome.
 
Tales was a G1 cartoon because its characters are derived from G1 toys. Pony “generations” are numbered for distinct toylines or their redesigns.
 
G1 toys didn’t use new moulds for “Tales”, so they’re not a new generation in any way even if the G1 TV series settings are very different. Tales is definitely not G2 and it’s not considered “G1.5” either. Say hello to G1 Bon Bon.
 
G2 didn’t get a TV series or movies, but it had newly designed toys, comics, and other media. You could use G2 as an example in the test to demonstrate why generations aren’t named after TV series changes.
 
G3 got a big redesign in 2009 that affected the toys and the movies. But the toyline stuck with the same characters, so folks called it G3.5 to avoid a complete version bump. To see what I mean about the redesign, compare G3 Cheerilee and G3.5 Cheerilee.

There was never a Generation 2 cartoon. Generation 2 did not catch on well enough to merit one.
 
My Little Pony Tales is considered Generation 1.5 and portrayed the characters in more domestic situations with modern life commodities such as electricity, television, and phones.

@Mirth  

 
Yeah, that was I thought.

@Kholchev  
I didn’t say there weren’t any differences, I was pointing out that you couldn’t tell between G1 and G2 anymore when there is no G2 cartoon.  
At least, that was my impression of what you said, that you thought Tales was a G2 cartoon. Right?

@Mirth  
But there’s large difference between this and this: >>695443  
And they both tagged as G1.

@Kholchev  
Here’s a start: There is no G2. It only exists as toys & a computer game. Both cartoons before the G3 ones were G1.

I can’t find difference between G1 and G2 anymore…

can we add out of context?