The River, Royal Court Upstairs, London Medea, Palace Theatre, Watford 55 Days, Hampstead Theatre, London

The proverbial one that got away is always the whopper, the elusive prize catch. Well, it's a bit like that for some trying to secure a ticket to the Royal Court's keenly awaited premiere of The River, a darkening chamber play written by Jez Butterworth and starring Dominic West.

Obviously West is a big draw, and last year's long queues for Butterworth's previous stupendous hit, Jerusalem, made headlines. Nevertheless, the Court has tucked The River into its attic studio, and made more headlines by creating an on-the-day-only scramble for tickets – with its online allocation released at 9am. The try-and-try-again technique may succeed, though. The punter sitting next to me said he'd only failed the first time (naively reckoning there would still be seats available at 9.01).

The Theatre Upstairs is enthrallingly intimate, transformed into a log cabin, lit by paraffin lamps and flickering candles. This is the riverine pad where West's unnamed character, an artist with a passion for angling, brings his new girlfriend (Miranda Raison), to introduce her to night-fishing and to bare his heart. The place is, however, haunted by another woman (Laura Donnelly) – maybe a memory, maybe only imagined.

Butterworth's dialogue flips between wryly humorous, naturalistic exchanges and more stylistically heightened passages. The latter might describe an offstage sunset with blood-red and lilac-blue clouds, or the first trout that West ever netted. It exploded out of the mirror-smooth water then writhed on the bank – brown, silver, orange – like a bar of precious metal, like God's tongue, he says. Those speeches can sound obtrusively artificial, and this may be deliberate. Butterworth endows his characters with literary inclinations – reciting Ted Hughes's verse – and West refers to fishing as crafted trickery too, enticing the prey with fake bait.

A teaser, the drama plays startling games with time and morphs into a psychological thriller. West seems a sincerely smitten romantic, padding around the cabin in check shirt and socks, cooking while his sweetheart takes a shower, and declaring she's his one and only. Or is he a control freak, a fantasist, a serial womaniser with dangerous intentions who has to be given the slip? Rustling up supper certainly gains a sinister edge as he guts a trout with a flashing silver blade, hacks off its head, and slips its oil-slooshed body into a scorching oven.

Director Ian Rickson's cast are compelling, Raison lured by West but fighting back, and Donnelly developing a jealousy-mocking glimmer in her eye. The River may not be as great as Jerusalem, but it's a disturbing slow burn.

The home bird turns into a slaughtering avenger when her husband jilts her for a new bride in Medea. In Mike Bartlett's disappointing new English adaptation of Euripides' tragedy, which he has also directed for the touring company Headlong, Ancient Greece has morphed into modern suburbia. Rachael Stirling's Medea is going psycho in a bland, red-brick two-up-two-down. A punky scruff with a posh accent and a vicious tongue, this Medea is horribly rude to her well-meaning neighbours. She plunges her hand into a boiling saucepan as she dishes up tea to her traumatised, mute little boy, then she dreams up worse horrors for her ex, Adam Levy's Jason – even as she tempts him back for a final fling. Bartlett notably makes Jason a reasonable guy and Medea a desperate loose cannon, but his staging is hit and miss. There are strong supporting performances, but Stirling left me peculiarly cold.

The end of another soured relationship looms in 55 Days, Howard Brenton's history play, commissioned by Hampstead Theatre and superbly premiered by director Howard Davies. The subject here is a "domestic" on a national scale – the groundbreaking English Civil War – which ultimately, of course, severed the body politic from the crowned head of state.

Brenton homes in on the fraught final weeks of the reign of Charles I, in the midwinter of 1648-49, when Cromwell appears briefly to waver, claiming that he is waiting for God's guidance, while the monarch – though defeated in battle and under guard – continues to insist he is the Lord's anointed, with dangerous eloquence, and scorns the parliamentary court trying him for high treason.

This is an epic clash of ideals. It's messy as well, riven by sub-factions, doubts and fears. Yet 55 Days simultaneously manages to feel human in scale and have an overall, strongly hewn clarity in its narrative structure. Apart from a few slightly wobbly accents, Davies's production is fine-tuned and engrossingly close-up, played out on a narrow traverse stage with battered swing doors. Only Charles Stuart (Mark Gatiss on outstanding form) is in period finery, affecting a cavalier stance in black velvet cape and silk breeches, haughtily resisting the march of time. Everyone else is in modern-era jack boots or suits.

This works remarkably well, tallying with Brenton's script which is only occasionally laced with 17th-century phrases, and it encourages you to see parallels with the Russian Revolution or contemporary warmongers who think God is on their side. Douglas Henshall's Cromwell is fascinatingly mercurial too, wracked by panic but then displaying a cut-throat determination. A covert moderate or a new dictator in the making? Well worth catching.

'The River' (020-7565 5000) to 17 Nov; 'Medea' at Northern Stage, Newcastle (0191-230 5151) 30 Oct to 3 Nov, and touring to 1 Dec; '55 Days' (020-7722 9301) to 24 Nov

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Critic's Choice

Denise Gough is electrifying as the new bride entangled in a love triangle in Eugene O'Neill's rural tragedy, Desire Under the Elms, at London's Lyric Hammersmith (to 10 Nov). James Graham's absorbing new comedy, This House, at the NT Cottesloe (to 1 Dec), dramatises the whips' tussles for supremacy in the hung parliament of the 1970s.