Farewell/Half a Glass of Water, The Playhouse, Derry

With the ongoing Loyalist protests on the streets of Belfast over the flying of the union flag, Field Day Theatre Company's ambition to probe political and cultural identity is as relevant today as it was more than 30 years ago.

Set up in Derry in 1980 by the playwright Brian Friel and the actor Stephen Rea, the company has returned to its spiritual home as part of Derry-Londonderry, UK City of Culture 2013, with two young Northern Irish writers, Clare Dwyer Hogg and David Ireland.

Farewell, Dwyer Hogg's debut, is directed by Rea, who also plays John, a former IRA quartermaster turned informer. He is clearly waiting for someone. Long-time Field Day collaborator, set designer Bob Crowley, re-imagines the remote Donegal cottage in a dull red, the colour of dried blood, haemorrhaging around the picture of the Sacred Heart.

There are clear parallels with Denis Donaldson, the IRA volunteer and top-ranking Sinn Fein member who was shot dead in 2006 in a similar location, after being exposed as an informer for both MI5 and the then Royal Ulster Constabulary.

Dwyer Hogg has a strong ear for speech. John's wife, beautifully played by Brid Brennan, recites what her husband likes to eat with the gentle beauty of a love letter. The ghost, Patrick, tells how he surprised himself by saying "please" to his killers. It pushed all the air out of the room as it fell, because it fell as the last "please" in a lifetime of pleases. This is a confident debut.

Half a Glass of Water by David Ireland is a two-hander. Rea plays Eli, Conor MacNeill is Whitney. The two men sit at either end of a long rectangular table. A fluorescent light hisses above. A half a glass of water sits in the centre of the table.

The setting is ambiguous. A prison visit? Friends meeting in a pool hall? A therapy session? The dialogue is brutal and tender, horrific and humorous. Graphic descriptions of male and female rape segue into declarations of love and into one-liners delivered with the comic timing of a seasoned stand up.

Rea is sensitive and sinister, the man who raped Whitney in prison, now his friend, and his confidante. MacNeill captures a damaged young man, trapped by years of abuse. In a post-conflict Northern Ireland, this is a tough, challenging work, undercut by Ireland's trademark black humour, which asks questions of what a successful post-conflict society looks like.

Stand out performances from the actors and sensitively directed by Lisa Hogg.