Hello everybody,

I've just arrived in the "dead city" but I'm left with only 1 minute air at the checkpoint. I can't see any filters in sight and I keep dying because I basically can't breathe. Will the game give me some more air if I die enough times or can I just drop the game without being able to finish it? Is there any way to get some more filters?

Seems to me there was a box or something around there with a couple filters. If you can't find any, you could always load an earlier stage and make sure you have some filters next time.

Easily the most frustrating part of this game - I so wish it had maintained the ability to buy filters (it's so artificial that you can't).

One thing you can do, though it's annoying and exploits a silly mechanic, is to take your mask off ASAP. Proceed to run around for... oh, five or six seconds, until your breathing gets really dire, then pop it on just for a moment. Lather, rinse, repeat. You can stretch a minute out to ... oh, certainly five, more if you're not too distracted by things and use the mask too much.

Thanks guys, but I'd already managed to finish the game a while ago... sorry for not mentioning that before.
It was damn hard, and the ending was totally unexpected... very, very good game, in the end.