Improving Freemium Design – Monsters Invade: Oz

In this series of Improving Freemium Design we're going to look at an indie game Apple featured called Monsters Invade: Oz and see what they did right and what could be improved.
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I first saw Monsters Invade: Oz (MIO) at the GDC Play booth this year. I was drawn to it by the graphics and description of “catching monsters similar to Pokémon.” However, like most times I visit a GDC Play booth I find the atmosphere too difficult to stand there and play and really immerse myself in the game that I’m checking out. I don’t know if it’s the crowds, the music or the fact that I know industry people are standing behind me and watching, but I just can’t find myself getting a good opportunity to analyzing the game. I left the demo of the game confused on mechanics or reason of why I’m playing, but I said I’d give it a try when it launched so let’s take a look!

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What they did right

Art & sound

I really dig the art. The hand drawn characters fit well with the concept of “ink” and the music is just as cool, unique and fun.

The icon is also unique (in a good way). It sticks out against other apps

Collection mechanic

I’ve been playing Pokémon since it made its début in ’95 so of course I can dig the monster collection mechanics. I often feel like collection mechanics are under appreciated. Look at all the looting systems in hardcore MMO’s to the looting mechanics in non-traditional genres like FPS’s like the Borderlands series. There’s no reason why these mechanics can’t also be in used in casual or mobile titles as well.


MIO allows players to spend premium currency for permanent and temporary modifiers. The permanent ones are a no brainer, but quickly get too expensive for non-paying players which is a great encouragement to monetize without being pushy. The temporary ones allow players to get a leg up on a battle if they need to. Not pay-to-win because players still need to hit the meters right, but certainly pay-for-competitive-advantage.


Permanent modifie


Temporary modifiers before each battle

Short-session friendly

I can fire up the game and have a meaningful experience within maybe ten seconds. This is key for mobile games because you need to remember that some players are playing out of impulsive boredom. They might just be waiting in line somewhere or waiting for their wife to try on clothes. Having a game that can scale with the player’s time is the best way to approach game design on mobile. Remember: easy to play, difficult to master.


MIO has three forms of currencies; ink, gold bars and books. Players can only purchase gold but in turn can be used to purchase ink or books. Most F2P titles need a dual currency structure and many can benefit from even a third. DragonVale was one of the first games I remember with a third currency and it was the #1 top grossing iPad app of 2012, and #4 top grossing on iPhone. Did the third currency really help them achieve these rankings? I believe so, because monetization comes down to sinks and sources within your game. In theory, the more things you allow (or even force) players to purchase then the more valuable the currencies become.

What could be improved

Delay balancing

I know F2P games need delay, but there was some serious delay in MIO. Once I burned through the initial ink (which acts in a similar way as energy) I earned maybe 200-some ink per day if I logged in once or twice per day to fill up my dog’s “ink.” That might sound like a lot, but that only heals my monsters maybe a couple times and I have to heal with almost every battle. As a non-paying player, I can only fight a few monsters before needing to quit. Perhaps this tight of a delay is working for MIO but if that’s true, then there must be a lot of whales or a lot of paying players.


608 for a week’s worth of waiting

Compounding delays

Not only do I regenerate ink at a very slow pace, but I need to wait several hours to “train” or revive my monsters. Sure almost all F2P games have delays that measure in hours, but normally you’re not hit with that long of a delay right away. First monster I caught took 2 hours to train before I could use him. Second took 6 hours. Players wait just as long for monsters to revive if defeated. 

I waited 6 hours and came back to find that when your monster revives, it revives with no health! I didn’t have enough ink to heal him so I ran from the battle. Walked around until I encountered anther battle and found out that I can’t run anymore either! I then had to wait for other monsters to heal, for ink to regenerate and now I couldn’t run. As a player, I did feel like I was getting hassled. 

I did find out eventually that you can continue to escape battles if all your monsters are dead. It doesn’t do a whole lot of good besides running around the map on a collection quest, but at least I wasn’t locked out of the game.


This section is about excessive pop ups. This section is about excessive pop ups. This section is about… enough already! I enabled notifications and it was only a matter of hours before I went into my settings to remove the notifications for this game. The fact is some users will uninstall over removing notifications. Leading up to disabling notifications, I was receiving one an hour. There’s no logical reason why they should be messaging more than once per day, and even that might be considered borderline too many.

No means no, Facebook

The first time I played the game I was asked to connect with my Facebook credentials. I elected to. The next pop up asked me to allow posting to my friends on my behalf. I elected no. Almost every time I’ve launching the app since, I’ve been asked to allow posting to my Facebook friends and my answer is and will continue to be NO! I understand there are some really successful games with aggressive Facebook strategies (I’m looking at you Candy Crush) but I don’t think it’s a good idea for all games to be aggressive. There are factors that will make it more acceptable like audience, genre and current level of success.


I love to quest. Games like Skyrim are dangerous for me because there’s just so much to do. MIO also has quests, but so far they haven’t varied much. I either need to pick things up on the map, defeat or catch so many monsters or walk in front of something. I understand that mobile games need more simplicity, but I think this is too simple.

Confusing map graphics

For anyone who’s played a JRPG (Japanese Role Playing Game) you know that you can search pots, open chests or interact with NPCs on the map. MIO has chests but you can’t interact with them (even though a closed chest implies you can open it). It has characters on the map (and sometimes they animate) but you can’t interact with them. The first time I was playing I was so confused why they were on the map if I couldn’t do anything with them. I was especially confused with the little animated mushroom men. I kept tapping on them, or running into them expecting that they did something because they were moving, but nope. Nothing.


Why can’t I open these chests? WHY?

Battle mechanics

I like how simple it is, but I don’t like how repetitive it is. It would’ve been nice if different monsters had different ways of attacking instead of the same timing meter attack. Another issue I have with the meter is it varies with opponents that I meet and I can’t seem to find out why. Is it because certain colored monsters have weaknesses towards other certain colors? Is it per monster and not per color? Does level matter? I can’t seem to figure it out and the game never explains why.

Another thing is the computer never misses but I do. It’s possible I could never miss as well if I hit the meters right every time, but I can’t do that. It makes the missing subject even more frustrating when my monster has low health, I’m out of ink and my ability to continue playing is hinging on being able to hit the center of the meter when it’s spinning back and forth at a crazy-fast rate for unknown reasons to the player.

Little Box Apps had a serious advantage against other indies because they were featured by Apple, but if you look at the top grossing charts (below) you can see that MIO has likely hit its peak in revenue.


Chart publicly available at

I think the major lesson to take away from this is optimizing before global launch, or if you know a platform has interest or will feature you it’s crucial to get the monetization piece of your game nailed down to maximize revenues from such an awesome opportunity.

If you’d like to talk about this or any other games you can find me here at my blog, the NativeX blog or on Twitter.

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Ben is a producer/designer who has collaborated on hundreds of titles on mobile, console, PC/Mac and social platforms. The titles have been from kids’ pet nurturing titles, to mature rated zombie shooters and everything in-between. Outside of video games, Ben is married, a proud father and loves motorcycles and other toys that are fast!