I thought this week's episode was o.k., but really felt like an inferior rip off of the Impossible Planet two parter from last season, brought down even further by the contributions of Torchwood's lead writer.
Like the spin-off, it constantly featured characters acting obliviously, rebelliously, incompetently and inanely despite apparently grave danger - e.g. the "tool getter" griping about being told to help as if she'd rather go read a book or complain to her union rep.....and some completely nonsensical plot devices:
Why are there 29 locked doors to the auxilary power? Why are they only unlocked by trivia questions? Why did nobody bother to write the answers down if they were so crucial - oh yeah, everyone's incompetent and unprofessional in Torchwood's world. If the Doctor can survive outside the space ship so close to the sun just wearing a space suit, why doesn't he just put on the space suit and enter the room with the TARDIS, which is surely a tad cooler, and just get everyone out of there.
They've also really got to stop making David Tennant's Doctor omniscient - in the past, the Doctor wouldn't just "automatically immediately know" everything (such as that the sick guy was infected, and that he couldn't be cured), he was just a really smart guy who would figure things out through investigation and deduction.
Lazy, lazy, lazy writing. This season badly needs at least a single episode that's knocked out of the park.