Whenever a video game character uses his Limit Break, a portrait of him or close-up of his face is flashed on the screen just before he proceeds to beat the crap out of his enemy. This allows us to see the determination on the attacker's face that would otherwise be difficult to convey on the character's in-game sprite or model. If the model is detailed enough to convey emotion, then an alternate option is to have the camera temporarily zoom in on the attacker.
When used with an image, this trope is frequently referred to as a "cut-in."
See also Eyedscreen, Versus Character Splash.
Its predecessor Marvel Super Heroes has a Super Move Sound Effect: a deep "X!" for X-Men (a holdover from X-Men: Children of the Atom) or "Infinity!" for other characters (which also carries over into the first MvC game for the returning cast from MSH).
Jojos Bizarre Adventure Heritage For The Future shows this for supers and "custom combo" inputs; in the latter case the portrait lingers for a second or two and the character's facial features twitch to give some semblance of not being just a still image. There are also "defeated" portraits when a super move KOs a combatant.
In Jojos Bizarre Adventure All Star Battle, Heart Heat Attacks (HHAs) zoom in on the character launching the move. Great Heat Attacks (GHAs) show a momentary cutaway in the style of manga panels as the character winds up.
Done in the BleachFighting Games. Taken further, unleashing Bankai causes a short cutscene of their personal activation method to play.
Final Smashes in Super Smash Bros.. Brawl tend to zoom in on the character using it immediately before the effect.
Samurai Shodown V had a variation. Portraits appeared not when a character used a super attack, but when they activated "Mu no Kyouchi" mode (which dramatically slows down the opponent).
The Mahjong Fight Club series has in-game AI-controlled avatars of real life Mahjong professional league players. Whenever one of them wins a hand, a cut-in of the pro's face flashes on their opponents' screens right before declaring the win. The pros themselves also have special user accounts that allow them to play as their in-game avatars (with a "real-life person" tag in place of the usual "CPU"), which will have the same effect, though the pro will see his/her own facial cut-in on his/her own screen as well.
Street Fighter III and Street Fighter IV both use the zoom-in, screen freeze, flashy lights variant when a Super Art is activated. SFIV goes one step further, and uses full motion zoom-ins for Ultra Moves, to enhance that Oh Crap feeling.
Rumble Roses uses this whenever any wrestler performs one of her two finishing moves.
Starting around 2002, the WWE series of games (formerly WWE Smackdown or WWE Smackdown Vs Raw) began adding more cinematic touches to the fights, typically dramatic zoom-ins, slow-mo, camera pans and/or repeating replays of successful finishing moves. In previous games you could invoke this trope in singles matches.
Skullgirls uses black-and-white portraits of characters behind fast-moving film reels, in keeping with the game's film noir aesthetic.
Aquapazza has this for each of the characters' Splash Arts.
In Ougon Musou Kyouku, characters' portraits swoop in when they make meta-declarations or counter-declarations, and they get one or more for their meta super attacks. Even support characters' portraits appear for their assists.
Guilty Gear Xrd goes the SFIV route and has cinematic startups to certain supers.
Persona 4 Arena has multiple cut-ins appear during the animations for certain SP Skills.
Hack And Slash
If it's been a Koei hack and slash franchise, it's used this trope. They seem to favor extreme close ups over still portraits, but that's mostly dependent on the franchise. Almost all of the Dynasty Warriors and Samurai Warriors games have used extreme close ups of the character model, often from multiple dramatic angles.
In Castlevania: Portrait of Ruin, when initiating a Dual Crush attack, the portraits of the two protagonists will flash on screen in a brief time-stop moment, accompanied by the characters shouting the incantation.
Even Dance Dance Revolution started doing this in SuperNOVA 2, flashing a portrait of the dancer in the background whenever the player gets high Combos. (20 or higher, with another portrait flash for every 50 combo)
Hottest Party 3 took this up another notch and made it more awesome. Starting from 50 combos the character will make a move on screen, and from 100 to 200 combos, so on, they'll continue to make a fancy celebrating move for it. And better yet, if you end off with a full combo, they'll have a finishing move while "Full Combo Finish!!" flashes on screen. Distracting for easily distracted players, but it's still very awesome.
Elite Beat Agents and Osu! Tatakae! Ouendan have the portrait of the lead member appear whenever the player completes a particularly good string of beats or hits a specific number of combos.
Role Playing Game
The Tales Series uses this for its strongest attacks, known as Mystic Artes (Hi-Ougis) or Blast Calibers, depending on the game.
Tales of the Abyss has two grades of Mystic Arte, one which gets a little portrait of the character and the strongest ones, which you can't get in the first playthrough and show a full pic of the character in dramatic combat pose.
If you're on a Tales of Hearts New Game +, you have a chance to see Kunzite's Mystic Arte use a different portrait from normal - specifically, with his helmet off.
Persona 3 shows a close-up of the hero every time you use a fusion power. Portraits of the Personas involved will appear to his sides.
It also randomly shows a cutaway of the character's face when their Persona either hits a weakness or gets a critical hit (and the first time they summon in battle, regardless of how it hits). It applies both to the party members as well as enemy Persona users (and the optional superboss.)
Finally, when you've knocked all enemies down, a character will remind you (via portrait pop-up and a voice-over) to initiate an All-Out Attack. Agree, and the screen will throw up the portraits of all characters participating in the attack.
Persona 4 features your party's portraits when they perform one of their follow-up attacks. In addition, the random face cutaways are still present.
The PSP remake of Persona 2: Innocent Sin added these to fusion spells. Everyone participating in the spell appears on the screen, usually with some loose bit of clothing or their hair flapping about as a side effect of summoning their Personas.
Fusion attacks in The World Ends with You: Level 1 Fusions have Neku's portrait on the bottom screen, and his partner's portrait on the top screen, each in a colored horizontal bar. Level 2 Fusions have the two portraits side-by-side, in colored vertical bars that stretch across both screens; this one of both characters with their eyes closed, opening them simultaneously. Level 3 fusions have full-body, non-bar portraits of the two characters in fighting poses circle each other once or twice before the attack starts.
From the third generation of Pokémon games onward, Pokémon using a move outside of battle (Cut, Fly, etc.) flash across the screen and cry before performing the action.
It also happens when you're challenged by a Gym Leader.
The final battle of Final Fantasy VI manages a sprite-based variant. When Kefka begins charging his Forsaken attack, a small sprite representing his laughing face will appear on the battlefield. When he appeared in Dissidia: Final Fantasy the same attack reappears as his Limit Break and a more traditional close-up of his face is used before pulling back to show the attack.
The final boss of Final Fantasy VII made the most of its newfangled 3-D graphics to give the final boss a dramatic face close-up when he performed his infamous Supernova attack.
Super Robot Wars: Endless Frontier has two cut-ins for each character: one "normal" one and one showing part of the attack in progress - Harken turning his super revolver into a beam cannon, Aschen removing her personality limiters (and significant chunks of spandex), and so on. They also pop up whenever you switch characters or summon in support characters to join in on the beatdown, and the second game makes them even more elaborate and increases their number greatly as well because of all the support-only characters. It also cranked up the ammount of butt-shots andbouncy breasts.
Taken up a few notches with Utsuho's, wherein the portrait is accompanied by large, yellow, radiation-symbol-spammed "CAUTION!" text scrolling across the screen as well as a blaring klaxon. Reason for this being that she is a living thermonuclear weapon.
Characters in Otomedius flash their portraits when using a P-Burst or D-Burst attack. The portrait is different depending on which Burst is used.
In Wolf of the Battlefield: Commando 3, the M-Crash special attack is accompanied by a cut-in portrait.
In the newer games, the Magichange ability also does this (As shown in the trope picture).
Some normal moves do this, as well, the Prism Rangers' Prism Justice (Squeezes the portraits of all seven of them onto the screen), and Mid-Boss' Adonic Buster and Super Adonis (A four person team attack and magichange respectively, both using copies of himself) being particularly noteworthy.
Disgaea 4 takes this Up to Eleven with the Prism Rangers ultimate attack. It shoves 13 portraits on screen at once!
Simillary, SD Gundam G Generation post SEED uses this in anything stronger than vulcan and punch attacks. This is because you're basically create your own robot army, so cut-ins are used to show who is in your mech. Story-based G Generation games uses cut-in to show the character's pulling out ID Commands.
Advance Wars shows a portrait of the CO whenever they use their CO-Power.
Team/Group Attacks in Chaos Wars show face cut-ins of all the characters participating in the combo. When a unit performs a Realize Special, a larger portrait of the unit is shown, and during the attack, just before landing the final blow, a face-cut in appears.