Although LL originally means “logical leftism”, the expression gradually extended to a whole logic-focused, comprehensive playstyle. Here are the differences, in terms of strategic impact, between LL and the style commonly played on BGA.

1) You don’t systematically play leftmost when you receive a clue hitting multiple cards.
You do when it’s logical, i.e. when it is obvious that your teammates would have clued you earlier if the playable card were not the one on the left.
More detail here.

2) You sometimes (rarely) play from the oldest spot.
More detail here.

3) You can save with color. Because sometimes it is more efficient than value. And because sometimes it is the only good way to save.

4) You can save non-unique cards, especially 2s.
Same with 3s if either the matching 1 is visible or in play, or if the target player’s hand is easy.
4s are the lowest priority but may be saved if the matching 2 (or the matching 3 & 5) is visible and the save doesn’t require too much sacrifice.

5) “Chop+newest” clues: whether you should play newest is situational, not systematic.

6) Finesse/bluff is used in the following cases:
- when you really need to respond to prevent a bomb, i.e. if the clued player is actually going to play (sometimes they know the card is not playable so you need not respond);
- when the given clue really doesn’t make sense unless you have just drawn the card that fills the gap.

7) LL is a more prudent, even conservative playstyle that requires players to envision all possible tricky situations.

Other LL articles:

LL in a nutshell
When NOT to play left
Is LL inferior to CL?
LL think chart