TETRIS: Is it possible to play forever?

Players may lose a game of Tetris for the following reasons:

• They can no longer keep up with the increasing speed, or
• A specific implementation of the game without very responsive control and without lock delay fails to keep up with itself when the pieces' downward velocity is much more than the maximum lateral velocity the player can apply to a tetromino. In other words, the possibilities for tetrominoes' movement are limited to the shape of a triangle in the playfield on faster levels. Once the triangle no longer covers the entire bottom rows of the playfield, as in level 29 of the NES version, this ceases to be the game's inherent challenge and becomes what some players call a design flaw.

The question Would it be possible to play forever? was first encountered in a thesis by John Brzustowski in 1988 and has been more recently investigated in published articles by Walter Kosters. The conclusion reached was that a player is inevitably doomed to lose.

The reason has to do with the S and Z tetrominoes. If a player receives a large sequence of S tetrominoes, the naïve gravity used by the standard game eventually forces the player to leave a hole in a corner.

Suppose that player then receives a large sequence of Z tetrominoes. Eventually, that player will be forced to leave a hole in the opposite corner without clearing the previous hole. Back and forth, the holes will necessarily stack to the top. Since the pieces are distributed randomly, this sequence will eventually occur. If played long enough, and the random number generator is theoretically perfect, any player will lose the game.

Practically, this may not occur. Some variants allow the player to choose to play with only S and Z tetrominoes, and a good player may survive well over 150 consecutive tetrominoes this way. On an implementation with an ideal uniform randomizer, the probability at any given time of the next 150 tetrominoes being only S and Z is one in (2/7)¹⁵⁰ (approximately 2×10^-82). The expected wait until such a sequence occurs has the same order of magnitude as the number of atoms in the known universe. Most implementations use a pseudorandom number generator to generate the sequence of tetrominoes, and such an S–Z sequence is almost certainly not contained in the sequence produced by the 32-bit linear congruential generator in many implementations (which has roughly 4.2 × 10⁹ states). In fact, newer Tetris brand games from 2001 and later tend to follow a new guideline such that the randomizer generates all seven tetrominoes in a permutation at one time, guaranteeing an even distribution over the short term, and this randomizer allows the player to continue a game indefinitely in theory, often clearing all blocks from the playfield.

Several of the subproblems of Tetris have been shown to be NP-complete.

Source: Wikipedia
Play Tetris Online: http://freetetris.org
Official Website: http://www.tetris.com

Prince of Persia

Prince of Persia is a platform game, originally developed by Jordan Mechner in 1989 for the Apple II, that was widely seen^{[citation needed]} as a great leap forward in the quality of animation seen in computer games. Mechner used a process called rotoscoping, in which he studied many hours of film of his younger brother David running and jumping in white clothes, to ensure that all the movements looked just right. Also unusual was the method of combat: protagonist and enemies fought with swords, not projectile weapons, as was the case in most contemporary games. Mechner has said that when he started programming, the first ten minutes of Raiders of the Lost Ark had been one of the main inspirations for the character's acrobatic responses in a dangerous environment.

After the original release on the Apple II, Prince of Persia was ported to a wide range of platforms, including the Amiga, Apple Macintosh, DOS, NES, Game Boy, Sega Mega Drive, Game Gear, SNES, Sharp X68000, Atari ST and SAM Coupé. The game managed to surprise and captivate the player despite being at first glance, repetitive. This was achieved by interspersing intelligent puzzles and deadly traps all along the path the Prince had to take to complete the game—all this packaged in fluid, life-like motion.

Prince of Persia also influenced a sub-genre, which imitated the sprawling non-scrolling levels, fluid animation, and control style pioneered by Prince.

As the title suggests, the game is set in Ancient Persia. As a child, Jordan Mechner had enjoyed the tales from the The Book of One Thousand and One Nights and the settings for this game are changed to Persia. The Prince is an orphan, living on the streets. One day, he scales the palace walls to catch a glimpse of the Princess, whose beauty is like the "moonrise in the heavens". His feelings are reciprocated by the Princess, despite their class differences.

The game starts with the Sultan of Persia being called away to war in a foreign land. Sensing opportunity, the evil Vizier Jaffar seizes the throne for himself. The Prince is imprisoned, since Jaffar has designs on the Princess. The Princess is also imprisoned and she is given a choice with an hour to decide: marry Jaffar or die. The Prince has an hour to complete the game by saving the Princess and killing Jaffar.

The twist is that the game is played in real time, so the Prince must quickly complete the quest without breaks. On some platforms it is possible to save the game at the start of each level, though the time limit still applies. The only way to lose the game is by letting the time expire. If the Prince is killed, the game will restart from the beginning of the level, or in some levels, at a mid-way checkpoint.

The game also includes a power bar. Medium falls, blue potions, being hit by falling platforms, and sword hits take one bottle off the power bar, while major falls, being hit unarmed, falling or running on spikes and blades, kill the Prince instantly. The Prince can increase the number of bottles in his power bar by drinking larger red potions, usually hidden or in dangerous places, while the regular-sized Red magic potions restore one life each time they are consumed. There is also a green potion that made the Prince light-weight and one that made the screen flip around, depending on the level.

In the fourth level, the prince is forced to jump through a magic mirror that tears his soul apart from him, always leaving him with just one full bottle. The soul, depicted as a semi-transparent copy of the prince, leaves the screen and will appear in one of the last levels, with the sword drawn, fighting the prince. Since the prince cannot hurt his soul without getting hurt as well, he has to sheathe his weapon and rejoin his soul by walking into it. This also adds an extra bottle to the prince's power bar. In the game's last level, the Prince has to fight and defeat Jaffar, a master swordsman. The Prince is reunited with the Princess and all is well.

X-Box Remake!

The changes from the original include:

• Revamped, updated graphics featuring new character designs, extra animations, better visuals, and added lighting effects in high-definition video.
• New original fully orchestrated soundtrack (composed by Arnaud Galand)
• Some of the new animations are in fact new moves, allowing the player to roll, rebound off walls, and climb and descend floors quicker.
• Some characters are based on their The Sands of Time counterparts, such as the Prince, Princess Farah as the Princess, the Dark Prince as the Mirror Prince, and the Vizier as Jaffar.
• The inclusion of one checkpoint per level.
• Full 3D, in-engine cut scenes of important events, such as the freeing of the Dark Prince, the Princess choosing death over marriage (if the timer runs out), and so forth.
• An optional butterfly that points out correct routes for stuck players.
• The game can still be finished if the player takes more than 60 minutes in the default mode.
• Two additional modes: Time Trial (finish the game as quickly as possible) and Survival (only one life, one hour).
• An optional ghost that allows players to race against themselves from their best time through a single level.
• Twelve Achievements, most of which unlock during significant events in the story.

Commander Keen

Commander Keen is a series of video games developed by id Software in the early 1990s, which was successful at replicating the side-scrolling action of the NES Super Mario Bros. games in MS-DOS. The cartoon-style platformers are notable for their pioneering use of EGA graphics and shareware distribution, and because they were the first games by id Software (which went on to develop blockbusters like Doom and Quake). The games were also exciting to the PC gaming community of the time because of John Carmack's revolutionary smooth-scrolling graphics engine. Although developed by id, most of the Commander Keen games were published by Apogee Software, an already established MS-DOS shareware game publisher. Tom Hall is Commander Keen's designer and the creator of Keen's universe.

Billy Blaze is an eight-year-old boy genius who has constructed a spaceship in his backyard from old soup cans and other household objects, called The Bean-with-Bacon Megarocket. When his parents are out and the babysitter falls asleep, he dons his brother's Packers helmet and becomes Commander Keen, Defender of Earth.

In the first game, Keen is exploring on Mars when aliens steal four spaceship components that he must get back. The aliens are the Vorticon, a fierce dog-humanoid race that had an outpost on Mars. Keen travels through different martian cities, and eventually recovers all the missing parts. But when Keen gets back to Earth, he finds the Vorticon mothership looming over the planet, with its cannons ready to attack. In the second game, Keen infiltrates the mothership and has to disable each of the Tantalus Rays targeting different Earth cities. During this adventure, Keen learns that the Vorticons used to be a peaceful race, but were enslaved by the mysterious Grand Intellect.

After disabling the cannons, Keen travels to the Vorticon homeplanet, Vorticon VI. In the third game, Keen has to face the Vorticon masses in their cities, all ready to kill Keen. After fighting through many levels of Vorticon-infested cities and military installations, Keen arrives at the lair of the Grand Intellect. There he discovers that the leader of the Vorticons is actually his old school rival Mortimer McMire. In the final level, Keen has to disable the "Mangling Machine", a large apparatus with many crushing parts controlled by the Mortimer. Keen eventually defeats Mortimer and frees the Vorticons.

But unbeknown to Keen, the Mortimer he had defeated was only an android duplicate. The real Mortimer goes on to lead the Shikadi, a race of energy beings who name him the Gannalech. In episodes 4 and 5, he attempts to destroy the galaxy with the Shikadi Omegamatic, but Keen stumbles on a radio message mentioning the Shikadi plans. In the fourth game, he travels to Gnosticus IV, to learn more about the Shikadi from the Oracle. However, when he gets there he discovers that the guardians of the Oracle have been captured by the Shikadi, and are imprisoned in the Shadowlands of the planet. Keen travels through dangerous forests, caves, and islands, and is finally able to rescue all of them. The guardians activate the Oracle, which tells Keen about the Omegamatic being near completion, and reveals the location of the station, in the Korath system.

In the fifth episode, Keen travels to Korath III and enters the Omegamatic, in order to destroy its core, the Quantum Explosion Dynamo, and stop the destruction of the galaxy. After avoiding several defense systems, Keen is able to reach and destroy the device. There he learns that Mortimer was the Gannalech, and his true intentions are made clear - to destroy the universe. In the sixth and final episode, Mortimer has Keen's babysitter kidnapped by the Bloogs in order to distract him. After travelling to Fribbulus Xax, Keen explores the alien planet and saves Molly from being eaten.

Link: www.commander-keen.com

Contra

Contra is an arcade game released in 1987 by the Konami corporation. The player controls a commando who battles waves of enemies including humans, machines, mutants and aliens to reach his ultimate goal. Much of the game's popularity came from its two-player simultaneous gameplay, which was an uncommon feature in video games at the time of Contra's release. While successful in the arcades, the game became and remained widely popular and remembered when it was ported to the Nintendo Entertainment System in 1988. Contra was voted #1 by IGN.com as being the Toughest Game to Beat.

The original game was ported as Gryzor to the ZX Spectrum, Amstrad CPC and Commodore 64 by Ocean Software for their release in Europe in 1988, with the Commodore 64 version also being released as Contra in North America by Konami. Konami itself ported the game in 1988 to the NES for a worldwide release and for PC MS-DOS for a North American release, and made in 1989 a MSX2 version released only in Japan. The NES version is famed for its use of the Konami Code, and is sometimes wrongfully credited as being the first to use it (the NES version of Gradius was the actual originator of the code). The gameplay remained generally unchanged from the arcade game.

The NES version of the game was included as part of the Konami Collector's Series: Castlevania & Contra released for PC Microsoft Windows in 2002.

Since November 8, 2006, a version of the original Contra is available as an Xbox Live Arcade download for the Xbox 360, costing 400 Microsoft Points ($5.00). This version of the game was also offered as a free reward through the Xbox Live Rewards program. Gamers could download the game for free if they raised their gamerscore by 1500 points between March 12 and April 22, 2007.

Contra also appeared as one of the games in the Nintendo DS compilation Konami Classics Series: Arcade Hits.

Contra and its successors were heavily influenced by the action movies of the time, in particular Predator, Rambo and Aliens. The characters depicted on the cover for the North American version of Contra resemble Arnold Schwarzenegger as Alan "Dutch" Schaefer from Predator, and Sylvester Stallone as John Rambo from Rambo: First Blood Part II.

Mortal Kombat 4

Thousands of years ago, during a war with the corrupt Elder God known as Shinnok, Raiden was responsible for the death of an entire civilization. To avoid a repeat of this event, as well as to protect all realms from Shinnok's threat, Raiden waged a brutal campaign and, at a heavy price, exiled his rival to a dark place known as the Netherealm. A couple of years before the 1992 Shaolin tournament, the original Sub-Zero assisted the necromancer Quan Chi in obtaining Shinnok's amulet, the source of Shinnok's power to traverse the realms(as recounted in Mortal Kombat Mythologies: Sub-Zero). Now (1997), 2 years after Shao Kahn's failed attempt to seize Earthrealm, Quan Chi has allied himself with Shinnok and helped the god escape from his confines. With the help of an Edenian traitor, they enter the Heavens and kill most of the gods, but Fujin and Raiden escape and gather Earthrealm's finest warriors to fight them. The Raiden-Shinnok feud had burst open once again, but this time the battle could be won by mortals.

Initial reaction to the new 3D look of the series (as is often the case with long running series) was negative, but MK4 managed to be a financial success due to an aggressive advertisement campaign which included a set of live action adverts filmed in Mexico and a US-wide tour of the arcade version by the game's creators which helped spread the word. EGM was one of the magazines that referred to it as "the worst Mortal Kombat game" and said it had "laughably bad 3D combat" as well. EGM also quoted that in the retro section of one EGM it said that "they were wrong when they thought it was good" when they preveiwed it" back in EGM #99.

Tetris

Tetris (Russian: Тетрис) is a falling-blocks puzzle video game, released on a large spectrum of platforms. Alexey Pajitnov originally designed and programmed the game in June 1985, while working for the Dorodnicyn Computing Centre of the Academy of Science of the USSR in Moscow. Pajitnov has cited pentominoes as a source of inspiration for the game. He derived its name from the Greek numerical prefix "tetra-", as all of the pieces contain four segments, and tennis, Pajitnov's favorite sport.

The game (or one of its many variants) is available for nearly every video game console and computer operating system, as well as on devices such as graphing calculators, mobile phones, portable media players, and PDAs. Tetris has even appeared as part of an art exhibition on the side of Brown University's 14-story Sciences Library. It came in third place on the 2005 edition of IGN's 100 Greatest Videogames Of All Time. While versions of Tetris were sold for a range of 1980s home computer platforms, it was the hugely successful handheld version for the Game Boy launched in 1989 that established the reputation of the game as one of the most popular ever. Tetris's popularity has resulted in its appearance in the media. It was referenced prominently in the video-game oriented cartoon Captain N: The Game Master. It was also referenced in Muppet Babies episode "It's Just a Pretendo", The Simpsons episode "Strong Arms of the Ma", Family Guy episode "Prick Up Your Ears", and Futurama episode "Fear of a Bot Planet." Commercials also occasionally parody the game. Police Academy: Mission to Moscow alluded to Tetris by depicting the Russians trying to hypnotize Americans through a puzzle video game referred to as "The Game" in the movie.

Super Pang (1990)

Super Pang is a game for arcade and Super Nintendo that was created by Capcom. It was released in August 1992. This game is the second installment in the Pang series.

The game is a two player game. The object the game is to use your gun to pop bubbles that bounce around your screen. There are two different modes in this game: Panic Mode or Arcade Mode. When a player pops a bubble, it splits into two smaller bubbles. This happens repeatedly, but eventually, the bubbles get so small that they pop when shot. Occasionally, monsters will walk or fly on to the screen, these can be seen as a help or harm to the player. When the player touches a monster, they die, but monsters can pop bubbles. This is the next part of super pang with added stages.