I haven't yet talked specifically about Zombieville 2's design until now. Since we're in the final stretch of production, I feel pretty safe talking about the major design differences between the sequel and the original, and how in many ways it's a very different game. But first... pretty pictures!
At their core, both Zombievilles have the same basic format - the sequel is still a game of survival, ammo management, and shooting for your best score. Here are the things we wanted to change about the original though:
1) Once you get pretty good at the original Zombieville, its not hard to stay alive for 30 minutes or longer when starting from level 1, and to an experienced player the early levels are simply dull. For the sequel, we wanted each session to be far shorter - less of a marathon, and more like a series of sprints. I think a great example of this kind of game style are titles like Flight Control, or the recent Jetpack Joyride. The sessions are only a couple minutes long, so you can play one very quickly, or a dozen in a row if you're so inclined. It shouldn't take 10 minutes of playing before an arcade game gets interesting.
2) The original Zombieville's weapons are simply a linear progression of power. When the game reaches its peak difficulty, most of the weapons are useless except for the laser and rockets. In Z2, we wanted to make weapons have greater variety, and allow them to serve some purpose no matter what level of difficulty you're playing at.
3) Once you've set a high score and seen all of the weapons, there's very little incentive to keep playing the original game. This time around, we wanted to ensure that there was a layer of persistence beyond each individual session, and lots of things to steadily unlock over the course of many hours of play.
With these goals in mind, we made the following major changes to the original game.
Something you'll notice right away is that the game is no longer completely flat - it controls more like OMG Pirates! or Battleheart, allowing you to move up and down as well as left and right via a virtual joystick. This was done for many reasons - to accomodate multiple players more easily, to introduce the ability to run around enemies, and to give zombies greater variety as well - some of them will shoot projectiles, or explode, and you need to have a means of dodging these threats. Along with this change is the elimination of hiding in houses - instead, you will find ammo and money hidden in destructible objects that pepper the landscape. We figured smashing a trashcan or busting open a parking meter was more fun than hiding behind a door for a few seconds.
Another major change is that the game doesn't simply go until you die - instead the game is broken up into smaller sessions or "missions". You have a time limit before your evacuation chopper arrives, and the goal is to get as many points as possible in that time limit. If you've played the "mercenaries" mode of Resident Evil, it's similar in a few ways - getting kills in rapid succession builds up a multiplier and improves your score, and skillful play will extend the amount of time you have remaining.
Further, the way you acquire weapons has changed. Rather than buying them temporarily each time you play, and then losing them when you die, instead you'll permanently unlock and upgrade weapons with money that you accumulate over the course of repeated missions.
The catch: you can only bring 3 weapons with you on each mission, and each weapon has pros and cons. The basic pistol may not seem impressive compared to the rocket launcher, but it has a very high ammo capacity. The flamethrower is still quite powerful, but slows your movement while its equipped. Some weapons are more effective at point blank, others at longer range, and some are defensive in nature, like flash grenades which stun all nearby zombies. The idea is that you don't simply equip the three "best" weapons - each weapon will excel at one thing or another, and it'll be up to the player to discover the most fun and versatile combinations, or figure out combinations that compliment your partner's choices in co-op. And the best part? Swapping between your 3 weapons is super simple - each weapon has its own fire button in the corner, so whipping out the right one for the job takes a split second. No more clumsily cycling through a list by tapping the top left corner.
In addition to your 3 weapons, you also will equip 3 "skills". These are similar to the bonuses that different characters got in the original Zombieville - increased movement speed, health, ammo, damage with specific types of weapons, and so on. Weapons and skills alike have 5 tiers of upgrades too, allowing you to increase their effectiveness, rate of fire, ammo capacity etc. Oh, and did I mention there are 15 player characters? 30 achievements? Unlocking all of this stuff should hopefully keep you busy for quite some time.
Hopefully this answers most questions about the game. It's very far along, and we expect to submit it to Apple around the middle of October.