how dangerous are these kind of f2 f7 opening bishop / knight sacrifices in rapid ?

@najdorfplayer48 said ^

gambit ?

When it's Halloween, you can play the Halloween Gambit. Many people play like this on this day.
At level 1000 you can play ANY gambit.

I always think it's funny when people play 15+10 and play faster than increment lol. They queue for 15+10 and play at a 3+2 or 5+0 pace.

Pretty sure that line should go down.

"Halloween Gambit"

• Halloween Gambit is more or less playable, but does not fit the Nxf7/Bxf7 theme of this thread.
  
  https://lichess.org/1lJyXpKU#6

"At level 1000 you can play ANY gambit."

• Yes, that is true, but that does not mean you should play dubious gambits. If you become stronger and face stronger opponents, then the dubious gambits no longer work. You then have to switch to a more solid opening, and that takes time and losses. It is better to play a solid opening right away.

Here is an example of a correct knight sacrifice on f7

Depends on your opponent's level; at my level, I play the Ruy Lopez as White and sacrifice my e-pawn to delay Black's queenside development, thus being able to attack his castled king:

I don't like gambits since, by playing Bc4, my B gets hit by Black's d7-d5 push; in the Ruy Lopez it can't happen, but also you need to know some theory - you can't get everything in life.