You Get Knocked Down, You Get Back Up Again

You're playing a video game and some enemy runs up and knocks you down. Normally, if this happened in Real Life, you'd expect to be more vulnerable to future attacks. But, for some reason, these cold, ruthless mooks appear to have the proper manners to wait for you to get back on your feet before they take another swing at you, making the time when the player is on their back a form of Mercy Invincibility. Just as annoying is when the player is forced into making the same concession.

This tends to be one of the Acceptable Breaks From Reality—because when it's averted, it can be really annoying. See Mercy Invincibility.

Trope name misquoted from the Chumbawamba song "Tubthumping", for those of you who weren't paying attention to popular music in the late '90s. The line goes "I get knocked down, but I get up again" and the song is primarily about getting drunk.

Subtrope of Mook Chivalry. Contrast Kick Them While They Are Down and Finishing Move.

Action Games

 * Unless they're doing some sort of grappling attack on Isaac, the necromorphs in Dead Space are nice enough to just sit there waiting for him to get up before resuming their attacks.
 * Some Dynasty Warriors installments allow you to lie there on the ground, your opponent flailing impotently above you, while your Musou gauge slowly refills.
 * Sengoku Basara is similar to some extent. If you're stunned badly enough that you can't jump right back up, mooks will mill around waiting for you to recover and go back to destroying them. The same can't be said for bosses though, who will quite happily perform diving attacks while you're down.
 * Averted in the new series of Tomb Raider. You have to press a button to get up quicker or you'll be vulnerable taking your time to get up.
 * Mooks in Twilight Princess can usually be killed by the Finishing Blow skill when down, but if you don't get them in time, they're invincible until they're all the way up again. If you're in wolf form, though, you don't have that ability, so they're immune from when they get knocked down until they get back up again.
 * Averted in Onimusha - stand over a downed enemy and attack, and you'll run them through. For most mooks, this is instant death.
 * In Rune, the (mostly harmless, but very annoying) zombie enemies can only be killed by beheading or burning them, but can't be attacked while they're Playing Possum, so unless you hit them just right with a conventional weapon, they'll keel over and force you to wait until they get back up again for another chance to try and land a perfect slash at their neck.
 * The titular colossi in Shadow of the Colossus will not attack Wander while he is lying prone on the ground, unless the player leaves him down for too long or if the game's difficulty setting is on Hard. However, some Colossi (namely Cenobia and Celosia) will simply attack Wander as soon as he gets to his feet, which can result in a frustrating cycle of getting up and getting knocked over again, often until Wander dies or is pushed into a place where the Colossi can't reach him.

Fighting Games

 * In Super Smash Bros. all players are invincible while getting back up. Of course, this doesn't happen until you start the animation for getting back up, so players lying on their backs are fair game if they don't try.
 * While in the first two games getting hit by anything would instantly reset targets to their standing state, in Brawl weak attacks will cause characters to flop on the ground. Consecutive weak attacks can then keep them trapped on the ground indefinitely, leading to cheap tactics such as "laser locks".
 * Beat Em Ups such as Golden Axe and pretty much all games in that genre have no attacks that hit people lying on the ground.
 * The Combatribes averts this by allowing players to strike at downed enemies and even bosses low on health.
 * Quite a few Konami-made Beat'Em Up (X-Men arcade game, Vendetta, Violent Storm and Metamorphic Force) let you attack knocked-down enemies.
 * So do Fighting Force.
 * Most early Street Fighter games also have no way of hitting people on the ground, although later games have the occasional exception. In fact, throughout the SFII series, standing too close to someone who's been knocked down can allow them to get in a free throw or Dragon Punch on you.
 * To contrast, while you still can't Kick Them While They Are Down, many SNK Boss types were especially vulnerable during a particular frame while standing back up, to the point that repeatedly sweeping was the only reliable method of dealing with them. Depending on the game, sometimes it's physically impossible to get out of a trip lock, while other games allow you to stay on the ground longer to throw off their timing by making them sweep while you're still invulnerable on the ground.
 * Enemies in God Hand can't hit Gene when he's grounded. Gene, on the other hand, can, and you'll need the extra bit of damage.

Real-Time Strategy

 * Units knocked down in Dawn of War cannot be targeted and are immune to directly-targeted further damage until they get back up again, although AOE attacks like artillery can keep hitting them.
 * Averted in Dwarf Fortress: not only do knocked over units take full damage while being greatly slowed down, another unit can stand over them to keep them from getting up until they move to a square where no unit is standing. Once aimed attacks were implemented, being unconscious (though not just on the ground) left you incapable of dodging or blocking a potential Coup De Grace, with your only defense being armor.

Role-Playing Games

 * In most of the Tales (series), if either you or an opponent are knocked down that character is generally invincible or at least highly resistant to damage until they get back up. Notably averted in one case though with Senel from Tales of Legendia, who learns a series of throws that can be performed on downed opponents (although otherwise the trope still applies).
 * Averted in more recent titles, however, where allies and enemies alike only have a window of invulnerability during the actual getting up phase. Once someone's on the ground, hitting them to continue a combo is a great way to dish out damage without fear of retaliation. In fact, many attacks in Tales of Vesperia, such as Azure Blast and Wailing Blast, are invaluable for this specific purpose.
 * Brutally averted in The Witcher computer game - Geralt can kill any knocked-down enemy with a coup de grace... and any enemy can do the same to a knocked-down Geralt.
 * Averted in the Persona series where they use the "Press system" AKA "One more turn", characters who are knocked down take extra damage and can also be stunned.
 * There are even attacks designed to do extra damage to downed opponents.
 * Averted in Fallout and Fallout 2. Whenever a player was knocked down, they could be attacked repeatedly until they either died or got back up with a penalty to AP for that round. Fortunately, this also happened to enemies.
 * Averted in Dragon Age, where knocking people down is a major tactic for both player-controlled characters and enemies. One of the nastiest attacks in the game is Overwhelm, a skill of warhounds, wolves, and shrieks which both knocks down and grapples an opponent, holding them helpless while dealing massive damage (usually until they're unconscious or dead).
 * Dragon Age II has a whole mage specialization focused on knocking people down and/or throwing them across the room.
 * Also averted in Elder Scrolls games, where getting knocked down leaves you vulnerable and unable to react.

Shooters

 * Bouncers in BioShock (series) can knock you down, but do not attack until you get back up.
 * Annoyingly turned upside-down in every possible way in Left 4 Dead. You can shoot zombies that are knocked down, and zombies can get you when YOU'RE knocked down (either from an effect, or just incapacitated.) But God help you if you try to help someone up while they're still in the middle of the "slowly falling and flailing" animation...

Sports Games

 * Averted in boxing games, but completely averted in Mixed Martial Arts games such as PRIDE FC ({=PlayStation 2=}), the UFC games, and EA Sports MMA.

Stealth Based Game

 * In Assassin's Creed 2 Ezio can Kick Them While They Are Down, but enemies will not do so even though the Elite Mooks have moves that knock him off his feet.

Survival Horror

 * In Rule of Rose no enemy can harm you when you're down or getting up (right after getting up, however...), but the same applies to you, as you can't harm enemies that you've knocked down, either. There's a stomping attack, but due to a bug or poor hit detection that plagues the rest of the game it's almost 100% useless; if you stomp every enemy you manage to get on the ground during the entire game, you may hit maybe one or two of them.

Tabletop Games

 * In Warhammer Fantasy Battle Quest, the various fake death techniques allowed a warrior to avoid damage until everyone else was dead or gone, at which point the monsters would start poking or eating. It never occurs to them to poke or eat if the fighting is at the complete opposite side of the room, of course.