Duality ZF is a 1-4 player intense retro shoot'em up (Xbox/PC), which features dual play, the ability to control two fighters at once. It placed #1 in Canada and #5 in the world in Dream Build Play 2010 out of 350 games from 110 countries. Currently looking for XBLA publishment. Official website: dualityzf.com.

Videos | Screenshots | FAQ | Testimonials | Press | Articles | Promo

April 2009 Trailer:

Duality ZF, our upcoming dual play Xbox 360 2D shooter.
See more videos on our YouTube channel.

Interviews:

Contact us for interviews.  We will interview on the following topics in deep personal detail:

1. Duality ZF development.
2. XNA and Xbox LIVE Indie Games (XBLIG)* game development.
3. Indie game development as a two-man twin brother team.
4. Shmup (shoot'em up / 2D shooter) development.
5. Xbox LIVE Arcade (XBLA) and our efforts to eventually land an XBLA contract.
6. etc.

We have finished a Duality ZF interview as well as a Xona Games interview.  Contact us for interview inquires.  We will more than likely accept, as well as blog about your site on xona.com.

*Xbox LIVE Indie Games formerly known as Xbox LIVE Community Games .

Subscribe:

Subscribe to Xona Games on YouTube, Twitter, Facebook, and Vimeo.

Duality Innovation:

Duality ZF introduces a few innovative duality features:

1. DUAL-SL, a weapon system with spread and laser features. It morphs from spread to laser and back via trigger controls.
2. DUAL PLAY allows you to control two players at once. Its an underground concept born in Japanese arcades by expert gamers. DUAL PLAY offers double the firepower. It suits newcomers in easy modes and allows experts to challenge extended expert modes.
3. DUAL-HL, a prototype weapon system in development.

Firsts:

1. Duality ZF is the first video game to support DUAL PLAY natively.
2. Duality ZF is the first 2D shooter (shoot'em up, shmup) video game to support eight independently controlled fighters simultaneously.

Game Modes:

Duality ZF features multiple games modes:

1. HOME (8 stages)
2. ARCADE (8 stages)
3. BULLET HELL  (8 stages)
4. SURVIVAL (single stage)
5. SCORE RUSH (single stage)
6. BOSS RUSH (single stage)

HOME is the regular game.  ARCADE is what Duality ZF would have been had it been an arcade.  It is more exciting, more intense, and more difficult.  If you are a hardcore "shmup" fan, ARCADE was born for you, but will be enjoyed by all.

Each game mode has online scoreboards.

Gameplay:

Duality ZF has high-action, intense, quick-reflex gameplay.

Simplicity:

Duality ZF has simple gameplay. Move and shoot. No bombs that blow up everything on the screen. No powerups that power you down or switch weapons against your wishes, only powerups that improve your 32-stage spread/laser weapon. Move and shoot. That's it. Playing is about skill of missing enemy bullets with skill of shooting enemies down. There are no complex controls or weapons to master. Move and shoot.

Weapons and Powerups:

Duality ZF features two massively upgradeable weapons in one: a dual spread/laser weapon that can be switched to spread or laser, or various hybrids, at will.  It has 32 stages.  If you can stay alive long to experience the maximum firepower, it shoots 65 individual bullets per shot, all calculated independently of one another.  With a maximum of four shots onscreen at once, that's 260 individual bullets per fighter, for more than 2,000 individually calculated bullets onscreen at once with eight fighters.

The powerups have an artificial intelligence system that lures them to the players most in need, to always promote a balance of power.  These are guidelines only, and do not need to be followed.  Upon final death, the remaining powerups you would have had, had you had an extra life, spit out to all remaining fighters and friends.  The final fighter left standing will have be boosted in powerups to help battle out the remaining fight on its own.  (Also read the "revival" section.)

Revival:

Lost fighters and friends are revived at the beginning of each stage, so when you are the last fighter standing, try to beat the stage and kill the end boss to bring everyone back.

Control:

The Duality ZF fighter has the maximum and most responsive control possible.  It is extremely agile and powerful.  When you die, it is your fault, not because of poor controls or a slow fighter.  We challenge you with challenging stages, not with an inferior fighter with inferior controls, to realize your true 2D shooter potential.

Release Date:

Summer 2009 in Xbox LIVE Indie Games (XBLIG)*, available to all Xbox LIVE users in the New Xbox Experience (NXE).

*Xbox LIVE Indie Games formerly known as Xbox LIVE Community Games .

Philosophy:

The Duailty ZF philosophy is:

Give the power to the player. The game’s difficulty should arise from enemy strength, not player weakness.

This subtle, but enormously important, rule of thumb is what sets Duality ZF apart from other arcade games.  Most games inhibit the player.  We power the player and challenge the player with more exciting enemy fights.

In Duality ZF your fighter is optimized for ultimate control.  That is why there is no fighter selection screen.  The Duality ZF fighter is already the best it can be in all possible forms of measurement.  In most games, it would be nice if your fighter moved faster (or sometimes slower); In Duality ZF we have optimized the fighter speed within 0.1 pixels per frame (that's a very tiny change in speed).  If we made it go any slower, an expert player would want it faster.  If we made it go any faster, it would begin to hinder an expert's performance.  That's gameplay optimization you do not encounter in other arcade games.  What results and lies in front of you is the most empowering fighter we could put in the game, which maximizes your ability to kick ass.  Duality ZF is not a joke to us; We want to see what you can do if given all the tools and powers you need.

Duality ZF is a 2D shooter (shoot'em up; shmup) made by 2D shooter fans. It is the 2D shooter that we have always wanted to play. It gives us great pleasure to realize this goal and (soon) share our dream with other 2D shooter fans around the world.

Scoring System:

Duality ZF's scoring system matches how much you dominate the game.  It is the most fair scoring system possible.  It cannot be exploited by tricky means.  The more you dominate the game, the higher your score.  Kill everything as fast as possible.  Kick the game's ass to get the highest score.

The scoring system awards points proportional to the enemy strength and attack.  The same formula is used everywhere in the game, across difficulty modes and even across game modes.  If the enemy is twice as hard to kill, you get twice the points.  The scoring system does not "care" about the difficulty mode or the game mode, only how tough the enemies are.

There is no maximum score or scoring caps.  If it were possible to kill an enemy one million times faster, you would get one million times the points.

Online Scoreboards:

Xbox LIVE Indie Games* does not permit us leaderboards, yet.  However...

Duality ZF uses a clever peer-to-peer score sharing system to implement online scoreboards, but peer-to-peer only works with Xbox LIVE Gold subscriptions. We highly recommend subscribing to Xbox LIVE Gold to fully appreciate Duality ZF's scoreboards.

*Xbox LIVE Indie Games formerly known as Xbox LIVE Community Games .

Soundtrack:

Duality ZF features a beautiful Imphenzia soundtrack, strong in club, trance, goa, and dance music.  It is a perfect unity to our hyper action gameplay.  Imphenzia tracks have exceeded one million downloads.  The Duality ZF Soundtrack will be made available for purchase and download on www.imphenzia.com upon release.

Duality ZF features an Imphenzia Soundtrack.

Trivia:

ZF is a military acronym for "Zone of Fire".  Duality ZF was original called "Zone of Fire".

"An area into which a designated ground unit or fire support ship delivers, or is prepared to deliver, fire support. Fire may or may not be observed." - Zone of Fire (mil.)

Dual Play Background Notes:

The port of the Raiden III arcade to the Playstation 2 (PS2) implemented DUAL PLAY before us. Technically, all simultaneous two player arcade games, like Raiden III, support DUAL PLAY. Anyone can play two players on any two player arcade game. DUAL PLAY is defined as one person playing two players on a multiplayer arcade game. In that sense, Raiden III did not *natively* support DUAL PLAY. (A fun fact is sometimes DUAL PLAY on an arcade game requires jamming the fire button down permanently.) One could also argue that all simultaneous two player console games support DUAL PLAY, too. However, it is difficult to use two console controllers at once, unlike two arcade controllers, as they do not have fixed bases. DUAL PLAY support in console games require implementing DUAL PLAY explicitly on one controller, as found in Duality ZF. So, in console games, this explicit implementation of DUAL PLAY where one controller acts as two controllers is what is considered to be DUAL PLAY support. Duality ZF is the first game to promote and attempt to popularize DUAL PLAY, and even attempt to standardize or coin or define it as "DUAL PLAY". Duality ZF is also the first game to support DUAL PLAY for multiple players. There is no other game where you can DUAL PLAY with two or more players; Duality ZF supports four DUAL PLAY players simultaneously, for an incredible eight independently controlled fighters on screen at once. Duality ZF recognizes there is only one player, and thus one score, for each group of dual fighters. Taking all of this into account, Duality ZF is the first game designed to truly support DUAL PLAY. It is much more than an implementation hack, like the PS2 Raiden III arcade port, like emulator hacks to allow one controller to feed input to two virtual controllers, or physical controller hacks which do the same thing. (Another fun fact is we did a controller hack on our Nintendo Entertainment System [NES] to control both players in Super-C [Super Contra] off one controller, back in 2001. The hack would work for any NES game, not just Super-C, of course.)

More Xona.com Links:

• Duality ZF March 2009 Tech Demo (video)

External Links:

• Duality ZF (official game site)
• Duality ZF Forums (hosted on xbox.com)
• Xona Games (YouTube, Twitter, Facebook, Vimeo)
• Xbox LIVE Indie Games* (xbox.com, Xbox Forums)
• Imphenzia Music (creator of the Duality ZF soundtrack)
• Dream Build Play (Microsoft's XNA Game Studio Contest)

*Xbox LIVE Indie Games formerly known as Xbox LIVE Community Games .