One of the cooler games I scoped out on the show floor at GDC 2014 was First Strike. It's similar to the nuclear war game Defcon, but built for mobile, and with a whole bunch of different game mechanics.
Players start as a major super power nestled in their respective corner of the globe. Slowly, players expand into neighboring countries and begin researching recon, efficiency, missile, and national military technologies. Then the stockpiling begins. Every country can store a handful of intercontinental ballistic missiles, and faster, short-range cruise missiles for defensive purposes. Research continues along in the background, but it doesn't take long before one player or another pushes the red button to launch the first nuke.
Every country has a First Strike option, which causes all armed allied countries in range to launch their warheads in tandem. This causes massive damage to a large area, but leaves your states vulnerable to counter-attack, since during launches countries can't do anything else. This forces players to constantly consider their overlapping defensive and offensive capabilities. After a few of your countries have been devastated, you can try reclaiming them after, but at the same time, you'll need to keep the pressure on any remnants of your enemy before they reestablish their foothold and begin producing weapons anew.
The game's graphics are simple and polished, with full 3D effects applied to UI elements, missiles, and explosions. A steady tick-tocking clock sound sets a forboding mood throughout, and the tongue-in-cheek "You win?" at the end of a match never makes you feel particularly great about what you've just done. Over time, you unlock new superpowers to play as, each with their own levels of difficulty. Some kind of online or local multiplayer would be nice to see, or a version built for phones, but as is, this is an outstanding single-player tablet gaming experience. Hey, no in-app purchases either! I think we've established that's a good thing.
As morbid as this game may be (and to be honest, it's a little less depressing than Defcon), a quarter of the proceeds made from sales are going towards the International Campaign to Abolish Nuclear Weapons and the Green Cross, which aims to repair environmental and human damage from industrial and military catastrophes.