 If you liked
Interlude
|
 ...then you might like
ChäoS;HEAd
|
Both series contain a strange atmosphere and a feeling.
In both anime, the main protagonist has delusions or rather feels as though reality is playing around with them. They meet a strange girl in both series that seems to be connected to his delusions and reality switches.
Chaos;Head is constructed in a more psychological way while Interlude takes a more philosophical approach. Still, the feeling of mystery is there as the main protagonist in both series struggles to deal with his reality.