is it possible to run just the game on the VPN while lets say browse chrome on my normal network?
I think it’s possible unless you use Full VPN mode in my opinion. 
For most of cases, mudfish should work like that.
doesnt seem like i use it but it still seems like when lets say i watch something online my game starts lagging so i assume everything goes threw the mudfish/
is there a way to check it?
Please check How do I know if its working? section and check the realtime graph whether it moves like that when you watch something.
If it reallt goes via mudfish program, the realtime graph will be dramatically moving.