What follows is a snapshot – by no means a complete list – of the year’s most affecting breakthrough screen performances.

JONAH HILL & MICHAEL CERA (SUPERBAD)

Though the 24 year-old appeared in no less than nine films in the last two years, Hill was given his first starring role as Seth, a foul-mouthed, manic, deeply loyal friend who is terrified of change as his high school graduation looms ahead. Hill, also a budding screenwriter, is roll-on-the-ground funny (witness his scene-stealing turn as a disco boot buyer in The 40 Year-Old Virgin), but the vulnerability that shone through his performance transformed what might otherwise be a penis-joke skit of a movie into a moving tale of growing up and, inevitably, apart.

For his part, Cera, 19, first introduced to fans as George Michael Bluth in the wonderful and, sadly, cancelled “Arrested Development,” is a master of soft-spoken comic timing.

WHAT’S NEXT: Hill’s screenplays Pure Imagination and The Middle Child are both set to be produced by Judd Apatow, and you can catch him alongside Jennifer Garner in Ricky Gervais’ directorial debut, This Side of the Truth, later this year.

EMILE HIRSCH (INTO THE WILD) It’s a mystery to me why Hirsch (23 in March) – known marginally for his roles in The Dangerous Lives of Altar Boys, The Girl Next Door, Lords of Dogtown and Alpha Dog – wasn’t nominated for a Best Actor Oscar for his work in this film.

Brilliantly directed by Sean Penn (also ignored by the Academy), Hirsch plays Christopher McCandless (a top student who gives up all his savings and an admission to law school to hitchhike to Alaska and live in the wilderness) perfectly, neither glorifying him as a noble hero nor dismissing him as a lunatic, but rather honoring him in a powerfully truthful portrayal.

WHAT’S NEXT: Hirsch reunites with Sean Penn, who plays Harvey Milk, California’s first openly gay elected official, in director Gus Van Sant’s upcoming Milk.

PAUL DANO (THERE WILL BE BLOOD)

Critics first noticed this 23-year-old as a wayward Long Island youth in the 2001 indie L.I.E., but many noticed his knockout performance as the mostly mute Dwayne in last year’s Little Miss Sunshine.

He follows up this year in Paul Thomas Anderson’s wonderful oil epic, as the young Evangelist preacher Eli Sunday, who stands in Daniel Day-Lewis’ way. Given an impossibly difficult task of shining in Lewis’ shadow, Dano’s creepy performance is very memorable.

WHAT’S NEXT: Catch Dano in Spike Jonze’s upcoming adaptation of Where the Wild Things Are.

MARKÉTA IRGLOVÁ (ONCE) Irglová (20 at the end of the month) and costar Glen Hansard, both of whose music powered this Irish indie film into the hearts of many filmgoers this year are nominated for an Oscar for best song for “Falling Slowly,” but they should be nominated for their amazing performances as love-weary, star-crossed friends as well. Especially when taking into account that Irglová had no prior acting experience whatsoever.