Heh, yeah, same here, I keep wanting to go back and do more.
It really is a pretty good tool I think, stuff is explained quite clearly and the positions are normally very interesting.
I just wish that they had a bit different scoring system... For example, most of Silman's positions are from the openings, like 8 moves in the game or so. It is extremely rare that there is just one supermega move in such cases, there is most often 3-4 good moves, with maybe 2 of them being a bit better than others and you choose between those 2 depending on your style. However if you choose "wrong" (not the move Silman intended) , you lose 30% immediately, even though it is a perfectly sensible and good move. You also lose 30% for making a completely ******ed move, so to me this does not make any sense whatsoever..
I just recently had to solve this standard position in French, were black basically had 3 choices: 1.. Nf5 (Attacking B on e3) and after 2. Bf2 play 2.. h5 , then 1.. h5 with the same idea, or 1.. Ba6 trading the bad French bishop immediately. I choose Ba6, because black can always play Nf5 followed by h5, while it might be too late to trade a bishop later on. The comment after the move says that Ba6 is a very good, sensible and CORRECT idea, but game continuation was better - boom -30%. Ok, give me -5% or -10%, but this is just cmon..
And then this might be nitpicky, but 1..h5 was the main move, while 1.. Nf5 and 2.. h5 was "alternate" move - why on earth wouldn't it be vice-versa, seeing how Nf5 and h5 is completely forced, and h5 has zero upside over it..?
Anyway, it is a pretty nice learning tool, maybe I am just a stat whore
/rant