Huge gamble

[Ace487]

All in
Normal Trap
Pay all of your life points then flip a coin: if you call it right you win the duel; if called wrong you gain 100 lifepoints. This card can only be activated once per duel and no other cards can activate to negate this cards effect.

[Whimsical]

Technically you would lose the duel before the card resolves (Since you can pay a cost, and can lose in the middle of a chain (As long as a card is not resolving)).
Some other things:
"Life Points" ('L' and 'P' are capitalized)
The : should be a ; (: goes after activation requirements, ; goes after costs)
Capitalize the first letter of the word that follows a : or ;
"Pay all of your Life Points: Toss a coin, and call Heads or Tails" (Coins are flipped at resolution, also it should be "Toss" not "Flip". If you're calling it then you need to state it, Lucky Chance is the only card that allows you to call the result so I'm using the card text from that)
". If you call it right, you win the duel, if you call it wrong, you lose the duel" (Again from Lucky Chance, though I dont know if it would still go on its own line. Also, don't use ;s except to separate costs from effects)
"You can only activate "All In" once per duel" (Modified from "The Seal of Orichalcos")
"Your opponent cannot activate cards that would negate this card's effect in response to this card's activation" (Modified from Night Shot, "that would negate this card's effect" might be wrong)

[AGATHODAIMON BANGTAIL COW]

You shouldn't have it have such drastic effects like "when teh doool!!11!!!! or lose it." This would become a troll card like Self-Destruct Button would, and neither this nor that should exist, TBH. By having this card played, it's like you saying "I don't feel like playing anymore. Let's flip a coin and see who wins, then go play <insert popular game here, of course it has to do with going around and shooting people> instead." Well, calling this wrong would keep you in the game, but you're close to losing anyway. We play Yu-Gi-Oh to play a card game (that isn't the other ones), not to flip coins and see how many times you call it right.

Instead, you could give it an interestingly somewhat-powerful effect if you call it right, and a [i]slight[/i] negative effect (or just nothing) if you don't guess right. The cards that already let you flip a coin usually have a really bad negative effect if they are called wrong, which makes it too risky to run for the good effect, such as how Time Wizard's potential Raigeki effect is overshadowed with it failing miserably and inflicting at least 250 points of damage to yourself (and losing your entire frontrow). If it didn't backfire so badly (and for good measure, had a slightly weaker effect), it would be a bit more playable than it is now. Sure, there are cards that help you win these coin tosses, but they take up space in the Deck that could be given to much better cards.

[Bahamut - Envoy of the End]

[quote name='Ace487' timestamp='1354981629' post='6088184']
All in
Normal Trap
Pay all of your life points then flip a coin: if you call it right you win the duel; if called wrong you gain 100 lifepoints. This card can only be activated once per duel and no other cards can activate to negate this cards effect.
[/quote]

I... literally cannot believe what I just read....

Ignoring unimportant stuff like OCG and grammar, I just... cannot fathom what you were thinking when you thought this was a good or even reasonable idea.

A one-card instant alternate win condition, that can be played in any deck, sprung at any time, requires no skill, could save a player who has been completely outplayed all duel by winning it for them with one coin flip that isn't in any way a huge gamble to make, and just to rub a bit more salt in the eyes cannot be stopped by any negation effects. I just... how could you possibly think this is....

This is, without a shadow of doubt, the worst card I've seen on this forum.

I'm sorry, I'm not deliberately trying to be mean or pick on you, but it is.

[Miror B]

If I wanted a coin flip format I'd go back to when Sams had triple Gateway and Triple Shi En.

[Ace487]

HAAAAAAAAAAAAAAAHAAAHAHAHAHAHAHAHA woooooo *inhailing* i get your guys points.