Alright I'll put up a defence for Szcz if nobody else is, rule out the Villa game because that was a clusterfuck for the whole team and if you look at the teams form previously and since it might be considered a bit of an anomaly.
What mistakes has he made that has caused us to concede? Look over the results
Fulham - Backpost perhaps could do a little better but had to cover the near post, were 3-0 up near the end of the game.
Sunderland, penalty conceded by Kosc - never in keepers favour.
Marseille, Penalty - Same.
Stoke - Reasonably not at fault, was a volley on one post then hit into the other side of the net not really expected to get there and can be marked down as a great strike.
Swansea - Defence at fault, Sagna fell asleep and didn't stay with him/didn't make a tackle. Was a Mertesacker hit that deflected into Davies and he did his best to make himself big.
There was two moments where he has been mental and come out of his box - Villa, and Swansea where he should of cleared.
But for the Swansea game I thought he looked fairly impressive, was collecting lots of crosses with ease and was in control of his area.
Now if you look at Begovic's (touted as a potential replacement) last few goals conceded he hasn't exactly looked top class. I'll say this as well, didn't see much of the highlights or the whole Liverpool match but if Szcz makes that layoff for Giak to score I think he is getting slated by Arsenal fans.
Think I've come to the opinion that Szczesny mentally focussed and on his game might well be good enough for us, was good on the back half of last season after being dropped and seems to have carried that on. Just needs to keep that up.
Also you want an example of world class,
this is one of the best penalty saves I've ever seen, in a match that was vital for us and could of gone against us if they scored.