About Koya Rift

So, What is Koya Rift?

[youtube http://youtu.be/aPFlZLavFDE]

Koya Rift is an action-packed platform shooter that is built around circular, adaptive gameplay that emphasizes replay value by challenging the player with procedural content tuned to their skill level. In Koya Rift, the player must enter a hostile planet and destroy an alien race so the planet can be colonized. Each game, the player is dropped off at the surface and must venture into procedurally generated caves, earning upgrades and buying units as he goes along. The difficulty adjusts precisely to the skill of the player over time, providing them with a consistent challenge. The goal of the game is to provide a challenging, yet casual experience that’s easy to pick up and put down.

In-Depth Elaboration.

<as told by developer Zach Kehs (SunnyKatt)>


I view the story of a game as an underlying excuse for the gameplay. I wanted to provide players with a motive to partake in hours of senseless action-packed combat, while not at all caring for consequence, morals, or any of that other touchy-feely stuff. This feeling is synonymous with the mindset of the protagonists of the story – you play as a band of professional futuristic mercenaries on the search for planets to sell to governments for colonization. The world is too overpopulated in this future and the small environmental tolerance of humans forced acceptably hospitable planets into a position of top market value.

The mercenaries stumble upon this planet, claimed and named “Koya”, which is worth a fortune due to the gentleness of the natural environment (oxygen in the air, green plant life, bodies of water, proper planet mass for earth-like gravity). They then discover what they have soon named the “Phantoms”. The Phantoms are hateful, vicious creatures that have formed out of the technology of an ancient race, and the hatred between their own kind that caused their demise. The Phantoms are incredibly adaptive – they quickly managed to assemble and combine energy weapons like the ones the mercenaries used to damage them onto their own soldiers and fight back. The mercenary company is running out of metal to form their own fighting droids (harvested from a nearby asteroid) and cannot afford to leave the planet to get help, for a rival company or government might discover the planet and claim the wealth for themselves. Stubbornness and determination prevent them from leaving altogether. They have not wasted this many resources to quit! Ally scientists were able to estimate that the enemy is originating from a point near the planet core they call “the rift”. Their mission is to completely exterminate this race, and that means sending their best to find and destroy the rift (that’s you!).

You play an a “Lancer” – an extremely expensive and advanced human-manned suit that has the ability to wield “Lances”(very powerful and rare energy weapons from the ancient race on the planet) with stimulated telekinesis using the pilot’s brain. These suits, each carrying a highly trained mercenary, are dropped onto the planet inside of an orb that is used by the soldier to order backup in the form of robotic droids.


A game of Koya Rift is pretty straightforward – you find yourself above ground standing in front of one of the delivery pods from the mercenary mothership. Your minimap hides the area below ground – and you have no idea what awaits you. The terrain of each level is procedurally generated (meaning it uses advanced algorithms to make itself different every time, providing nearly endless possibilities. See Spelunky). Below ground lies a web of tunnels and caverns that is different every single time you play. It’s impossible to know what awaits you behind every corner. Procedural generation isn’t just in the level – all of your enemies will seem different too. Their size, speed, color, health, damage, and weapon behavior will be unique for each one you fight. Your own weapons are generated the same way – the Lances you bring along with you to levels are generated out of endless possibilities. One gun may fire large, single shot energy blasts that slow down and weaken all enemies in a large radius, where another gun will shoot bursts of many bullets that curve in every direction with a waving motion, another gun that fires several shots at once but can pierce through walls and home after enemies, and another that heals and enhances your allies.

General Chaos. (click to make bigger)

You have to venture down into the unfamiliar cave system and eliminate all of the Phantom Crystals (Where the enemy soldiers are grown). Unfortunately the Phantoms are hunting you the whole time, while their crystals evolve and grow. If you manage to destroy all the enemy crystals, you win the level.

Don’t get too proud though – if you beat it too easily the game will know and will be sure to adjust the difficulty for next time. Game difficulty in Koya Rift is complex – it’s not a simple modification to the amount of health you have, and it isn’t a simple easy-normal-hard scale. Difficulty is a very precise unit of measurement that expands near-infinitely in either direction in this game. If you beat your last couple of levels easily it will slightly increase, if you keep getting beaten down without a fight it will decrease to help you out. Difficulty adjustments affect almost everything in game – from the reaction speed of the Phantoms, to the speed at which they grow and evolve, to the cost of your allies, the experience they need to level up, the accuracy, size, fire rate, and density of your energy weapons,  the rate of health recovery, the effects of special weapons, the size of the levels you play on, the health and damage of your enemies, the speed and fragility of your allies, the cash value of killing an opponent, the swiftness and force of enemy attacks, and even more. There are so many values that change, and when they do change, they change with such subtlety that you will not be able to pick out exactly why this next game seems like more of a challenge for you than last, or why you’re finally able to beat that one level that you were stuck on for so long.

Duel in the caves! (click to make larger)

These items combine to create an excellent formula for expandable gameplay – in the end you have a game that you can always come back to and find something different, and always be challenged regardless of your ability.

I hope you enjoy it if you choose to pick it up. Support me by Donating, Buying the game (two links below, to whichever vendor you prefer), and, most importantly, spreading the word about this game!

There’s an old, small demo here. It has almost all of the features that make the game cool stripped away from it, so I recommend you use it to check if your system runs the game well, and if you like the feel of combat, I guess. Level Generation and Difficulty Adjustment don’t exist in the demo! Also, all the features I added to the game in the 1.1 update don’t exist in the demo either!

Contact is SunnyKatt@live.com , feel free to ask questions, give suggestions, ask advice, complain, praise, or whatever else besides spamming. I’ll usually respond to everyone.

Click the button below to buy Koya Rift through BMT micro. (this is a direct payment for a DRM-free copy that doesn’t require any other software to play!)

Click the button below to buy Koya Rift on Desura.

Desura Digital Distribution


46 Responses to About Koya Rift

  1. Pingback: “Koya Rift” announced! |

  2. CoveBIT says:

    Koya rift is becoming very nice.

    i would be a game tester for you if you want

  3. CoveBIT says:

    ok, will the game be done soon?

    i would buy it.

    do you need help with anything? (Better broadcasting, anything)

    • sunnykatt says:

      I’m aiming for around april next year. The most and best help you could offer would be to spread the word about the game, getting more people to subscribe to the website and pay attention to the game so there can be a bigger release when it comes out. Thanks for the support!

      • CoveBIT says:

        OK. i would spread it to the world.

        it would have been easier if i have got the game to take screenshots/gameplay vids. but you choose for your self.

        btw heres my email.


      • sunnykatt says:

        Haha, thanks. You don’t have to go around and market it, just tell your friends and your internet friends. I don’t advertise using the actual game yet because not only am I not entirely happy with it yet, but I also haven’t really officially announced it on any indie game websites.

  4. Darren Azaki says:

    Looks good. Sadly, I won’t be able to nab it when its done because I’m broke.

  5. Pingback: Trailer: Rift Koya (SunnyKatt) | Minijuegos

  6. Pingback: Koya Rift: An Indie Game With Limitless Potential | The Astringent Gaming Journal

  7. OriginOfBob says:

    Hello Zach,

    I’ve just done a write-up about your game for The Astringent Gaming Journal, and contacted you via email about getting more coverage of Koya Rift. I look forward to hearing back from you!

    Here’s my post: http://astringentgaming.com/koya-rift-an-indie-game-with-limitless-potential/

    I hope it brings more attentive eyes to the seemingly excellent work you’re doing!

    Take care,

    • sunnykatt says:

      Great article! I’ll reply to your email, and mention your article in my next blog update. Thanks man!

    • Shahid says:

      Hey, I just bought the game and I raelly feels it needs to have a possibility for windowed mode, and preferably so that the game pauses and mutes when unfocused. Other than that I think so far its been great

      • sunnykatt says:

        Hey man, your comment got caught in the spam filter for some reason. I almost deleted it but then I noticed you sounded like an actual person, sorry about that.

        You can already do both of these things, actually. If you press F4 the game goes into windowed mode, and then if you click out of the window focus it will pause and mute the game. Hope that helped!

  8. blockempire says:

    Look cool. 😀
    I’m QuantumGames btw, but now representing BluInteractive. Hello again.

  9. Pingback: Interview: Zach Kehs on Koya Rift « Life's Not Simple

  10. Bebop says:

    Looks excellent, definitely looks like you put a lot of work into the graphical department.

    Unfortunately I’m just a teenager without a job for the moment, so I’m unsure if I’ll be getting it right away or not.

    Still, I hope you make some well-deserved money off of this game, because it looks and sounds great.

    May I ask, what compiler (or game making program) do you use?


  11. Bebop says:

    Oh, excuse my question:
    “May I ask, what compiler (or game making program) do you use?”

    I’ve just read that you use Game Maker. I’ve been using Game Maker for some time myself. Anyway, good luck with this game, and I hope inspiration still flows in you; like I’m sure it did when you just started making it.

    • sunnykatt says:

      Thanks a lot, I really enjoy words of support from people like you. Unfortunately I did a really poor job of marketing it, so getting attention is going to be tough. 😦

      Don’t forget about me! 😀

      • Bebop says:

        I wont forget, I have a feeling I’ll be a fan of yours for a long time to come. I’ve subscribed for updates as well.

        When I see someone telling me how Game Maker can’t make good games, this could very likely be another example of a good game made in Game Maker.

        I really respect how far you’ve come with this game so far, low devotion to a project is the most common problem in the Game Maker Community, which is why the large majority of games made with Game Maker are very short and have nothing addictive about them, and you feel no sense of achievement.

        I’ll help spread the word of this game as much as I can, hopefully to audiences who could purchase it when it is released.

        In order to draw a bigger audience for yourself I would suggest releasing a little Demo on as many indie game development sites as you can find, after your games completion of course.

        Also, I’m not sure if you’ve ever come across this, but it could serve useful for you.

        That’s an anti-decompiler for Game Maker 8, which could very likely help you protect what you’ve spent so much time on from being stolen from you.

        (Sorry for the long comment!)

    • sunnykatt says:

      Thanks a lot! That means a ton to me. I’ll be releasing a demo either at the same time of or shortly after the release of the main game.

      I already use score_under’s encryption to protect my game, but thanks a lot for the link as well. 🙂

      Hopefully I can make myself an example for others to follow, not very often do people take GML to its fullest potential.

  12. Pingback: Koya Rift Interview With Zach Kehs | truepcgaming

  13. Pingback: Koya Rift « INDIEGRAPH

  14. indiegraph says:

    I have to say, stellar work. You’re a source of inspiration, SunnyKat. I’m tapping away about Koya Rift for indiegraph: have a look http://indiegraph.wordpress.com.

    • sunnykatt says:

      Thanks for the kind words man! Despite this being known as a “big” GM game, I’m having a very hard time getting the word out about it so it isn’t doing so well. (I am partially to blame, since release I’ve been very busy and haven’t done much to market it!) Articles like yours help a lot! ❤

  15. Dan says:

    Uh.. totally just bought this. Why hadn’t I heard of it before?

  16. Hi Sunnykatt 🙂
    Bought this after i saw people talk about it in the Rps comment section, always a great source for pc games.
    You even bothered to reply there 🙂

    I just finished my first campaign and had so much fun i wanted to give a bit of feedback.
    first of all what i like most is the sense of investment. Should i blow all my money for followers or keep some change for resurrections?
    Ive just put all my money into rank ups in the map selection. and bought many followers at the start so i kill a bunch of crystals before they spawn to many phantoms. Before that i had difficulty because i only used myself and my bad aim 🙂
    The colouring system for enemy priority is also nice and intuitive well most of thr game is really intuitive expect weapon coolours maybe since they are so many.
    Overall it just had great flow and at the the end i had 2 behemoths as a boss fight and found a white gun that complimented my follower army playstyle.

    Here i got a one time only bug though.
    I cleared out every crystal (checked the map) yet the mission wasnt over.
    i thought i had too kill the remaining enemies that would still spawn but they never stopped. reloading from the last savespot fixed it and i got to beat the campaign 🙂

    well ill just list the thingsi have criticisms about.

    Followers have very weak ai. i lose one of them at pretty much every turn. This is my biggest gripe because getting around with my army was a much bigger challenge then any enemy.

    Also slowdown in big battles if you want to hear about my hardware just ask but it should be quite adequate.

    oh and when i found a new weapon it was supposed to be almost always better then what i had efore so i wanted to switch eapons but couldnt remeber which one was new since they look very similar and i hadnt used 2 of my starting ones. maybe weapons you found in the cave should be marked in a special way in the right click selection wheel?

    p isnt the easiest button to reach with wasd, e and q are alot closer. why not have those as the default to open the shop?

    In pselunky you have multiple non combat things that change the way you get around like your phasing ability, abit more stuff like that that changes you playstyle based on the random chance of getting it or combinations of them would at to the light roguelikeness,

    The game is very addictive and motivating, though now i ofcourse dont get new unlocks i want to try dfifferen approaches and weapons, maybe next time ill try to start with a white gun and refine my mass minion approach or use the money to buy a sidearm an go low on minions.
    graphic style is alos excellent and the music too.

    This got rather long hope youll read it 🙂

    • sunnykatt says:

      Woah, thanks for taking the time to write this feedback! I’m glad you like the game!

      I’ll just respond to your criticisms really quick.

      1.) Followers do get stuck on walls occasionally. I hope to alleviate this in a future patch if I have the time. Sorry about that.

      2.) I did my best to optimize the game. It’s running on GML script, which is pretty slow and only limits me to one processor thread. I made tons of optimizations, but it still runs slower than a 2d game should. 😦

      3.) The newest weapon you have picked up will have a flickering yellow background when you right click to select it. They aren’t necessarily always better than your previous gun, they’re either equal to the average of all your weapons or slightly better than that average.

      4.) I do want to add more playstyle-changing things like phasing. I’m not sure what they would be or if I would have enough time to implement them though. 😦

      I’m very glad you enjoyed it. Thanks again for responding here!

      • Oh you are very much welcome 🙂
        The weapon thing is very helpffull! i also noticed that they are below your starting ones when you select which ones you can take with you.
        Ah if its an engine thing thats excusable.
        i also found that some of the weapons already change your playstyle quite alot.

        Btw have you contacted Total Buicuit?
        Getting indie titles “out there” is kinda his mission statement

        tell him your only fame on reddit :_)

        Thanks alot for replying helped me out with that weapon bit especially 🙂

      • sunnykatt says:

        Thanks for the feedback! And I have contacted TotalBiscuit. Despite that being his “mission statement” many places are not willing to support smaller indies like me. It’s a risk.

        They said he might include it in a multi-WTF in the future, which would be great. I watch his videos too!

  17. the p thing was bogus sinnce q , space and many others work. well it was my first impresions as clean as they go 🙂 i indeed used p everytime for some reason. played it some more since (:

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