Are the Penumbra games spec heavy? My PC is really lame :I

No they arent really that hard to run on older computers. You can try the demo on the website if you want to try it out. 
http://www.amnesiagame.com/#demo
 
Windows Requirements OS: Windows XP/Vista/7
Processor: 2.0Ghz
Memory: 2048MB
Disc Space: 500MB
Video Card: Radeon HD/GeForce 6 

" No they arent really that hard to run on older computers. You can try the demo on the website if you want to try it out. 
http://www.amnesiagame.com/#demo
 
Windows Requirements OS: Windows XP/Vista/7
Processor: 2.0Ghz Memory: 2048MB Disc Space: 500MB Video Card: Radeon HD/GeForce 6  "

So much for ''adding descriptions later'' ;P Although later can still be a very long time!