Mmm for the most part average and really hard to watch in terms of the budget. Not really much you can say here. The Dalek creatures offspring monsters in purple look rather silly. The Daleks once again look like fools to the Doctor.
The Doctor points out that the Daleks are vulnerable to subzero temperature so he and Thals lure to the spring of it and they die in funn fashion.
He then plans to use a Dalek decoy to get in. Everything goes according to plan until they are discovered at the end.
Run of the mill episode that given today's technology and budget might have expanded the episode from average to good.
Nonetheless for nostalgia it's entertainment.