Here are the complete primetime averages for GSN from this past Wednesday and Thursday in total and 18-49 viewers, plus how they rank compared to other nights:
Wednesday 8/12 (8-11:09pm ET): 390,000 total viewers; 141,000 18-49 viewers
This is actually a rather weak night in total viewers (very strong for 18-49's thanks to new Skin Wars) with Skin Wars in the middle that perks up the numbers. The Skin Wars rerun at 8pm and the second new episode of Idiotest were weak, which dragged the numbers down.
Thursday 8/13 (8-11pm ET): 449,000 total viewers; 113,000 18-49 viewers
This is average in total viewers and slightly above average in 18-49 viewers for recent GSN standards.
The truth is, Saturday and Sunday nights seem to be raising expectations for GSN because they're filled with Family Feud. Last Saturday, two hours of Family Feud in primetime averaged 546,000 total viewers while two hours of The Chase and Chain Reaction on Thursday night averaged 500,000 total viewers. So very popular Family Feud makes new GSN originals look sort of weak while they are actually not doing that bad.