Voltorb Flip
Voltorb Flip is a game at the Goldenrod Game Corner and Celadon Game Corner in Pokémon HeartGold and SoulSilver. It replaces the traditional slot machines found in past Game Corners, and appears in all languages of the games, except for the Japanese release, which still contains the slot machines.
Contents
Play
Voltorb Flip was described in a prerelease review as "a cross between Picross and Minesweeper".^{[1]} It features a fivebyfive grid of tiles, underneath of which are hidden numbers (multiplier cards which affect the player's coins) and Voltorb (which Selfdestruct).
Flipping a multiplier card will give the player that many coins on the first card, or multiply the total by the number flipped for all subsequent flips. Higher levels have more multiplier cards, therefore producing larger payouts. Flipping a Voltorb will cause the player to lose all coins earned during the current string of multipliers. Flipping a Voltorb also ends the game and drops the player down to the level equal to the number of multiplier cards flipped before flipping the Voltorb (flipping either 0 or 1 will cause the player to regress to level 1). At any time, the player can Quit instead of flipping more cards to end the game and permanently keep earned coins (though the level drop down rule still applies); doing so counts as a loss in terms of the next round. The player wins and advances one level by finding all of the ×2 and ×3 multiplier cards. Winning or Quitting, as before, will earn the player Coins, which can be traded for prizes. The only way to advance to higher levels is to win the round; level 8 is achieved by winning five games in a row of any level. Exiting the game will reset the player to level 1.
There is also a "Memo" mode where the player can set symbols with the Voltorb and the numbers 1 to 3 on every field which has not yet been flipped up in the current game. This can be used to indicate whether, for example, the player thinks a given tile can contain a 2× or 3× multiplier or only a Voltorb or a 1× multiplier.
Once the player earns the maximum of 50,000 coins, he or she will be exited from the game and will be unable to play further until spending some coins.
In each level, a certain amount of coins can be obtained. The higher the level, the more coins that can be obtained. Assuming the player does not quit, the interval is as follows:
 Level 1: 2050 coins
 Level 2: 50100 coins
 Level 3: 100200 coins
 Level 4: 200500 coins
 Level 5: 5001000 coins
 Level 68: 1000+ coins
Strategy
Voltorb Flip is luckbased in the fact that the placement of the ×1, ×2, ×3, and Voltorb cards are random. However, a strategy can be used since the game is gridbased and the player can see how many Voltorb and the sum of the multiplier cards are in each row and column along the bottom and right side.
If the total Voltorb in a row or column is 0, all cards in that row or column are "safe" to flip over. If a row or column meets a certain requirement (shown below), all cards left unturned in that row are either ×1 or Voltorb, and can be left unturned to complete the game. This is considered a "dead" row or column, the player should make sure to mark them so as to not forget and flip. If there is a row of only Voltorb, or all multiplier cards have been flipped, then the column contains only multiplier cards, or vice versa.
Rows or Columns with the combination of 4/1 3/2 or 2/3 can be automatically eliminated as there can only be a 1 or a Voltorb in them.
Dead row/column formula
Given:
 a = Total Voltorb in a row or column
 b = Sum of Multiplier Cards for a row or column
 c = Number of ×2 cards flipped
 d = Number of ×3 cards flipped
If a + b  5 > c + 2d, then the row is not yet "dead"  there is still at least one ×2 and/or ×3 card left to flip.
A second formula also may help to find dead rows and columns: Given:
 a = Total Voltorb in a row or column
 b = Sum of Multiplier Cards for a row or column
 c = Number of Unflipped Cards in a row or column
 d = Sum of Flipped Cards in a row or column
If c  a < b  d, then the row is not yet "dead".
A simpler calculation is also possible: Given:
 a = Total Voltorb in a row or column + Sum of multipliers in the same row or column
Subtract the multiplier of a card by 1 and then subtract the result from the a of the row or column; do this with all the cards from that row or column cumulatively, until the result is 5.
×1, ×2 and Voltorb formula
If Voltorb + Sum of multipliers in a row or column is equal to 6 and there's 1 or more Voltorb, all the cards in that row or column are either ×1, ×2 or Voltorb.
Reaction
The exclusion of the slot machines in European releases of Pokémon Platinum was met with wide criticism by fans. While no official word from Nintendo was given on the subject, it has later been speculated that the removal of the pseudogambling minigame was because of the negative stigma attached to gambling.^{[1]}. Another reason could be that the change is because of the implementation of more aggressive and stricter legislation in the European Union towards gambling. Instead of slot machines, European Platinum players instead were given game machines, which were largely uninteractive. This met with negative feedback.
The Voltorb Flip game is likely included to provide a fun alternative to the game machines. The initial reviews of the game have been positive, with Official Nintendo Magazine stating the game is "awesome".^{[1]}
Trivia
 The flipping aspect of the game bears similarities to card flip, a Game Corner minigame exclusive to Pokémon Gold, Silver, and Crystal.
 The Voltorb can be thought of as a dramatic way of saying ×0, as it is roundshaped. The game ends at that point because after multiplying the payout by 0, no other multipliers will ever change the total payout to anything other than 0.
 This game seems to be similar to the cancelled game Pokémon Picross.
 Unlike former games in the gambling corner, Voltorb Flip does not charge the player any money to play, which means that the only thing the player has to lose is the coins that he or she has collected in a game. This was probably intentional so as to remove the negative financial consequences of gambling from the game, thus making it more of a minigame.
In other languages

References
 ↑ ^{1.0} ^{1.1} ^{1.2} Prerelease review from Official Nintendo Magazine