Agree with all the recommendations so far.
Here's some more:
- The Orphanage
- The Chaser (Korean)
- Cold Fish (Japanese)
- We need to talk about Kevin
- Black Death
- Eden Lake
- Shauna (Finnish)
- Triangle
- Sleep Tight (Spanish)
- Confessions (Japanese)
- The Whisperer in Darkness
- Cold Prey 1 & 2 (Norwegian Slasher)
- Bedevilled (Korean)
- Martyrs (French)
- Dream Home (Hong Kong)
- The Uninvited Guest (Spanish)
- Pontypool
- Some Guy who kills people
- The Silent House (Uruguayan)
- Red, White & Blue
- We are what we are
- Kidnapped (Spanish)
- The Dead
- The Loved Ones (Aussie)
- The Revenant
- The Woman
Also you can try...
Retreat
The Ward
Outcast
The Shrine
Seconds Apart
Apollo 18
Ashes
Rabies (Israel)
A Serbian Film ;)