Personally, I would love to have a real sonic screwdriver, but as the Doctor is in desperate need of his one (to save the universe) I don't really have a choice.
Hold on, Miss Foster's sonic pen would also do the job...
Ok, let's try to be more serious.
First there is to say, "Waters of Mars" wasn't scary. Today's children are used to Harry Potter and stuff, so "Waters of Mars" didn't give even me the creeps, and I'm not exactly the biggest Harry Potter fan existing. But those children are. The beeb should check what they so-called "target" audience is watching on a normal Sunday evening before declaring something as "scary".
Further, I really disliked the last 15 minutes of it. Yes, now we can surely do a much better character sketch of the Doctor's recent regeneration, but I can't help thinking "it just wasn't worth it".
Controversially, the first 20 - 25 minutes were great. It was quite amusing seeing the Doctor not knowing what to do, dashing between decisions like an electron being shortly before reaching the right energy level to leave an atom. But what RTD made of this was a worst-case scenario. My main problem is no-matter when or on which planet Adelaide would have died this certain "fix point in history" would have been changed anyway. Except the Doctor knew this before saving the whole crew. The effect shouldn't have taken him by surprise. So, what exactly was he hoping for?
However, another way of seeing this is that the Doctor knows he is going to die, no matter what, so maybe he wanted to change a certain point in time to open Gallifrey's "time-lock". As a result, the last thing he might do is trying to save "them", the Timelords, as on a personal level there is nothing he could lose anymore.
Anyway, all in all RTD managed to reach his goal: As WoM ended in a very awkward cliff-hanger so he can be sure about having top ratings no matter what the beeb decides to put "End of Time" against with.
First things first, you can find a "Waters of Mars" YT link here, and I've found this nice guardian-review on the site of the already mentioned newspaper. You can take a look at it here. So, I think I don't need to give you folks a plot summary ;)
There will be some kind of a review in a few hours or days. Depending on... stuff. Anyway. I hope I will post mine before Lawrence Miles does.
So, I don't want to be responsible for you breaking your promises you made yourself. Here is a link leading to my source*. It's your choice ;). Maybe I'll edit it later, but right now I just don't find more or better information. Even our beloved guardian TV&Radio blogs aren't writing anything about it ATM.