2D Graphics for iOS - How does cut the rope do it?

I've been using unity for over a year now and have released a few very polished games. We decided to invest ($75) in 2DToolKit to help with our sprite management. Even after using 2DTK our builds still come out to just under 100mb and installed on the device take up close to a Gig. How do apps like cut the rope get their install sizes to <300mb and still have beautiful, crisp @2x & @3x assets?

I've been searching for a solution better solution for Unity, but the only things I find are from 2014. It's almost 2016 and Unity hasn't provided better support for this?

Please shed some light on how I can keep making beautiful apps that take up less space.

 

Any guesses? When supporting @1x and @2x my games take up 700mb+ of space when installed on the device. I have a ton of graphics, but I don't understand how games like Angry Birds takes up such little room?

 

I use 2DToolKit configured like this...
For @2x graphics, no single graphic is greater than 1024x1024.
For @1x graphics, no single graphic is greater than 512x512.
I don't use @4x.
With that said, my @2x graphics still look sharp even on something like an iPad 4 which has a resolution of 2048x1536px. I feel this is due to the limitations of our eye sight. A 1024x1024 graphic uniformly scaled up to fill the screen of an iPad 4 looks pretty good to me.
Using this approach, my builds come out under 50MB, which translates to approx 60MB installed.

 

Considering all the platforms it's on, it's quite probable Cut the Rope & Angry Birds are made in Haxe / Flash + Box2D. Those are very lightweight engines with many dedicated libraries and extensions that can use PNG compression directly on the device / platform. The footprint of apps made in Haxe is much smaller than that of Unity as it is a dedicated 2D engine, you have to remember Unity is a relative newcomer to 2D and file size is not going to be the same as a dedicated 2D engine.

 

Thanks for the feedback

 

Yeah, you'll probably get much smaller file size with tools that are especially made for targeting mobile platforms, such as Corona SDK etc. Funnily enough, as I live in Finland, I got kind of curious if there was any information about the technologies used by Rovio. Wikipedia says that for engine, Angry Birds (the first game in the series) was "SDL, Box2D". Angry Birds 2, released in July 2015, says "Unity" as the game engine.

Not sure how reliable the info on Wikipedia is. There was one source for the SDL part which was a testimonial on SDL website. But kind of interesting that they might be moving towards Unity on mobile platforms.

 

If you haven't already, make sure you have set up your TK2D Atlases to be PNG rather than a Unity Texture.

 

Good info @Sose! Thanks for sharing. My current game is 80% done, so unfortunatly I can't change engines at this point but it's still good to know about.

@DanielQuick - Good tip! Where would I change that setting? I can't seem to locate it.

Edit: Found it in the SpriteCollection editor under settings

 

Wow! Changing my sprite collections from Unity Textures to PNG compressed my payload from 750mb to 214mb! Thanks so much @DanielQuick! I owe you a beer!