IUGO had a hit on its hands with its original tower defense game, Zombie Attack. Now it puts you back in the position of a survivor of the zombie apocalypse trying to protect your "shack" with Zombie Attack! Second Wave. In other tower defense games, you play a "god" figure placing towers wherever you want on the map. ZA!2 adds the twist that you run around as the survivor and have to guide him to a particular spot on the map to build or upgrade a tower.
He carries a machete so you can fight off the hordes when your turrets are not enough, or when you need to cut a path to a tower to upgrade it. Your survivor has no fear of dying. Unlike most zombie games, the game is not over when YOU die. You will simply respawn after a short period. The game is over when the building/vehicle you need to protect takes so much damage that it is destroyed. Otherwise, it sports all the typical features of a tower defense game: multiple maps, multiple towers, upgrades to the towers, and multiple types of enemies to kill off.
ZA!2 gives you two ways to control the survivor, dragging him about the screen or tilting your device. Tilting feels the much better way to go as you can see the whole screen instead of blocking it with your finger. Though your fingers are in the way at times you can easily jostle your character out of that perfect spot you found for your next tower.
ZA!2 sports seven different towers, six different zombies, four different maps, two different outfits for your survivor and different game modes: Survival and Challenge.
(and possibly more, IUGO is vague abou this) is part of their IUGO VIP program. Basically, you send referrals to your friends to buy ZA!2 and if they put your VIP Code in the referrer space (mine is 12864 - hint, hint), you earn VIP point. These can be spent on getting exclusive In App Content for the game.
Survival mode is the classic tower defense mode. Zombies just keep coming and you keep building and upgrading towers trying to stop them. The zombies get tougher over time but this seems to progress really slowly.
Challenge mode is what gives ZA!2 all its re-playability. Challenges limit the types of towers you can build and vary the game play. The towers and the style of gameplay you have become used to while playing Survival often has to be radically altered to score enough points to get a decent "Grade" on each Challenge. Each map has five challenges so there are a total of 20 to keep you playing forever.
Seven weapons of cartoony goodness. Building the Choppa up to high levels just to watch the gigantic circular saws rip zombies to shreds is fun in and of itself. The Decoy creates a scarecrow copy of you that self-destructs after luring the horde to itself. Changing up your weapon strategies just to see all the abilities and animations is part of the re-playability of the game.
Four new maps. The first ZA only sported one map and it was pretty much just an open square. ZA!2's maps are larger than the screen.
You sometimes are not exactly sure how your towers on the far side are doing. You get some hints from the sound effects, but you often have to take precious time away from building/upgrading towers in your current position to check on the other ones. Plus, the new maps have built in obstacles and choke points.
Six zombies. The two zombies in the first game were not all that different from each other. In ZA!2, each zombie has definite strengths and weaknesses. For example, when you are warned that a high level Winged Horror is approaching, you quickly check to see if you have enough projectile turrets to fight it off... or else you may end up in hand to hand with it just to defend your shack.
Survival mode wears thin after a while. The zombies progress in strength rather slowly and often seem to stumble around having trouble with their path-finding (I am talking about BEFORE they have their heads blown off and this behavior is supposed to happen). That is, when they finally seem strong enough to overwhelm your defenses, they often just give up and wander off.
The upgrade system does not make a lot of sense. Building a few towers to high strength causes low-end towers to cost a fortune to upgrade. I know this is an attempt at play balance, but it seems arbitrary. If there were any real rhyme or reason to the prices, I might not mind, but I could not find a pattern (at least not while in the heat of battle).
Plus+ and OpenFeint are becoming the de facto standards for High Scores but ZA!2 doesn't implement either. Of course, IUGO's online score system is nothing to sneeze at. :)
Fans of the first Zombie Attack! definitely need to get Zombie Attack! Second Wave. Graphics, zombies, turrets, maps - all are massively improved. So much so, that if you DO buy ZA!2 there is absolutely no reason to buy ZA! if you do not already own it.
Except for having to control your character to place and upgrade turrets, ZA!2 does not really bring anything new to the tower defense genre. This is not to say that it is a bad game - quite the opposite! ZA!2 is fun, engaging, challenging (well, not so much in Survival mode) and has a great atmosphere. Is it worth the $3.99 price tag? Not in my opinion. If it goes on sale for $1.99, I would snag it up....maybe even for $2.99 if I were really hurting for a new tower defense game to play.