Weird analytics for a needless sacrifice

Hello there!

I've just played a game and went to analyze it. Game here:

I was having a look at my bad moves, noticed I could have played 12 differently, so I investigated. Surprisingly, the analysis reported white response Na3 and Nc3 as alternatives. 

Can someone explain how is this possible ?

Thanks!

I'm not sure why it posted them that way...but anyway, neither move is satisfactory.  13 Nc3 simply hangs the exchange, and 13 Na3 also fails (to 13... Rxa3 14 Bxa3 Nxc2+ when Black gets a won game by taking either piece).

Incidentally, I liked the combo you played (although you also had 18... Rxc3 since if 19 Qxe5 there's 19... Rxe3+).  In fact, I suspect the combo was even stronger than you thought, since 20... Rxc3+ is mate in 2.   20... Rxc3 also works on 20 Ke1 (although 20... ed looks pretty good there too).

Oh yeah, and there was also the cute finale 22... Rfe8+ 23 Kd6 Rc6#.  An unusual mate indeed!

You walked your opponent's king like a dog!