Need help understanding Tactics features

Hi, all. I'm new here and have been trying out the Tactics exercises. I notice that after the exercise is completed, there is a space at the top of the screen with two different rows of moves. I presume they are alternate ways of playing the game (starting from the position given).

For one puzzle, I wrote down the alternatives, set up my board with the original starting position, and began playing through the moves. I found an "impossible" move (...Kf7) — impossible because there was a black pawn on f6. I double checked, and I saw I had copied the moves correctly.

What am I missing here? I noticed that when I replayed the puzzle, a different set of "alternate moves" appeared at the top of the screen, with a different points (i.e. +4.36, etc.)

Sorry for the long post. I'd appreciate your help understanding this. Thanks!

Where exactly are you talking about? Tactics Trainer doesn't show anything like that so I'm not sure what feature is showing that.

I can't post a screenshot from my iPhone, but I'll try from my computer in a few minutes.

Here is a screenshot:

Ah, so the app and you're looking at the solution. 

 

So, in that it is giving the engine evaluation of the top two moves for black from the initial position after white moved to Qd4.  It's hard to say exactly you were seeing in that first example but the white king should have been able to go to f7, even if there was a pawn on f6. Now, if there was a pawn on g6 or e6 then it wouldn't be possible.

Thank you, Martin, that helps a lot!

Now for my other question. Unfortunately, I didn't take a screenshot, but I did the same puzzle once before, and in the space at the top of the screen, there were two separate solutions (?). I'll post them, and please forgive the lengthiness. Those were the ones that confused me. I only worked through the first one, and couldn't get all the way through because of the aforementioned "impossible" move (9...Kf7). Here they are. I appreciate your patience.

 

First line:

(+4.36) 1.f4 Ng4 2.h6+ Kf8 3.Bh3 Qxc2+ 4.Qxc2 Rxc2 5.Kxc2 Nf2 6.Rh2 Nxd1 7.Kxd1 Bxd5 8.exd5 f5 9.Rc2 Kf7 10.Rc6 Ra8 11.Bf1 Ra7 12.Kd2

 

Second line: (just a snippet for the sake of illustration)
(+3.05) 1.Bh3 Nxf3 2.Qg2 Qxc2+ 3.Qxc2 Rxc2 {ETC.}

It's hard to say without seeing the initial position. If that analysis is from either the end or initial position, I'm not seeing a tactic in your last 25 that looks like it might match.

I think the initial position is the same as the one in the photo. It was just a prior iteration of the same exercise...

I think I'm undergoing newcomer's growing pains, Martin. I'm just starting to figure out how to use the different features here. Your answer did help me, and I appreciate it. I have a feeling I'll be asking a bunch of silly questions in short order. 

Tha makes sense. White, in that tactic blundered by playing Qd4. The analysis is telling you that white was winning and f4 should have been played instead. In that case, move 9, ...Kf7 is possible since on move 8 the f6 pawn went to f5.