I'm really not even sure what to make of Gundead Defense [App Store]. It's a free tower defense game set in 1885 where cowboys are battling zombies in the wild west. While the premise is beyond ridiculous, the gameplay is extremely solid and it even features some functionality I haven't seen in other tower defense games before.

Gundead Defense follows the standard tower defense formula in that there are creeps traveling down a set path that you need to defend. Instead of placing towers, you position members of your posse armed with different kinds of weapons. You can also dispatch different henchmen down the path to fight with the creeps to supplement your defenses, which creates this interesting second layer of strategy to the game as you not only need to manage placing and upgrading members of your posse, but you also must strategically order your henchmen to attack to exploit the weaknesses of the various zombie types.

In addition, there's also a multiplayer mode where you can either play on a single device, or with two devices via Bluetooth. When playing via Bluetooth, both players play at once on a split map and you can see where your opponent is placing towers and everything. It's really cool, and again, I can't believe they're not charging for any of this.

The included single player has seven maps and features both a quick play mode and a story mode that focuses on your posse robbing a bank and being jumped by zombies. There's also a single 99¢ DLC level pack that adds an additional seven maps and allows you to play as the zombies who have completely different abilities. Purchasing the DLC pack also will let you play as the zombies in multiplayer.

I've been having a great time with Gundead Defense, and highly recommend downloading it. If you somehow haven't played a tower defense game before, this freebie is an excellent introduction to the genre.

App Store Link: Gundead Defense, Free

In early February we were tipped off to a mysterious announcement on Ubisoft's web site regarding a multiplayer Assassin's Creed game exclusive to the iPhone and iPod touch. Last night Assassin's Creed II: Multiplayer [App Store] was released, along with the surprising promotional price point: Free for the next 48 hours.

AC2: Multiplayer initially appears to be an extremely simple game. Players are matched with other assassins online, and then pick up assassination targets to determine which player they need to kill. Following this, you wander around town until you find them, then tap to assassinate. Doing well in a game seems to actually require a surprising amount of skill, as you need to walk with the other civilians around town, matching their movement as much as possible, all the while looking for other civilians who are moving irregularly or are somewhere they wouldn't normally be.

The game is loaded with several different power-ups, online leaderboards, a friends system, and other cool unexpected features. It's even under 20MB, so you can download it over 3G. In two days it's going back to its normal price of $2.99, so be sure you grab this game while it's still free.

App Store Link: Assassin's Creed II: Multiplayer, Free (For a Limited Time)

Much like Eliminate and TouchPets Dogs, ngmoco's We Rule launched first in Canada this afternoon. Since We Rule heavily relies on the Plus+ network, this limited Canadian release is allowing ngmoco to make sure they've got all their servers working properly before the game is unleashed to the rest of the world. They haven't said when they're going to throw the switch to allow everyone else to download We Rule, but looking back at the limited Canadian releases of previous ngmoco games, it wouldn't surprise me to see We Rule in the US App Store sometime next week.

We Rule is a kingdom building game, somewhat similar to the massively popular Facebook game Farmville. Here's what we had to say about the game from our hands-on preview at Macworld San Francisco:

The game map shows you your kingdom as well as the kingdom of your Plus+ contacts. Scrolling across the map shows you the relative size of everyone's kingdoms. The goal of the game is to build up your community as much as possible, but with the added twist that your own kingdom can be customized with a number of special cosmetic tweaks. These tweaks will make your kingdom truly unique and personalized.

The game consists of alternating between your daily activities of harvesting or otherwise managing your resources while building up new houses, farms, and businesses. Your kingdom will be bustling with activity from townspeople as it grows, though unlike God Finger, you don't actually have individual control of the inhabitants. …Read More.

We'll have a review of sorts when the game hits the US App Store, but in the meantime, if you're lucky enough to have a Canadian iTunes account and are looking to add kingdoms to your network, my Plus+ username is simply "Eli". (Although because of how the Plus+ search works, you're probably better off searching for "Hodapp" or "Eli Hodapp".)

Admittedly, my kingdom is fairly pitiful right now.

Canadian App Store Link: We Rule, Free

If it weren't obvious by now, ngmoco has completely shifted gears from their former business model of offering "premium" priced games to free to play "freemium" games. Eliminate [Free] and Touch Pets Dogs [Free] were just the start of the pricing trend that will likely permeate the rest of the ngmoco game lineup for the foreseeable future.

A number of things can be attributed to this shift, in a Gamasutra interview with ngmoco VP Alan Yu, he cited 50% to 90% piracy rates, and discussed the increasing difficulty in selling iPhone games at a $9.99 price point as the market drives itself to rock-bottom 99¢ pricing. Free games can't be pirated, and the explosion of Facebook gaming, as well as the success of the various Epic Wars and other similar games on the App Store solidified the validity of the free to play model before Eliminate even launched.

The unfortunate side effect of all this is that Rolando 3 as it originally was envisioned is left as the odd man out, per an IGN interview with Neil Young, founder and CEO of ngmoco. Since ngmoco currently has no plans to release games that aren't free, the Rolando franchise has been sent back to the drawing board until they can figure out a sensible way to deliver a Rolando game as a free to play experience.

Even though there may not be a Rolando 3 anytime soon, I still recommend trying out the existing Rolando games on the App Store if you haven't already. The original Rolando [$2.99 / Free] as well as Rolando 2 [$4.99 / Free] are both absolutely fantastic games, making excellent use of both the touch and tilt controls of the iPhone.

Free games are almost as awesome as free samples at the grocery store, or maybe more awesome depending on how you look at it. Three cool games are free today, and like most price changes, they will only be free for a short period of time so it's best not to wait before downloading these games.

Alchemize, $2.99 → FREE

Alchemize looks to be a simple match 3, but the gameplay is actually quite complex with all kinds of things to unlock, different game modes, and other surprises. We liked the game in our review, and it's really worth checking out to see how they managed to mix up the match 3 formula.

While I wasn't really crazy about this naval tower defense game when it was first released, it has since been updated a ton with all kinds new content, gameplay tweaks, achievements, and OpenFeint integration with online leaderboards.

Where most word finding games have you frantically searching for words to beat a timer, Textropolis has much more laid back gameplay that allows players to search for words made from the letters found in the names of 30 different included cities at their own pace. If you like Textropolis, check out the sequel, Fishtropolis [$1.99] as well.

Well, readers, that special day is upon us. It's Valentine's Day. And what better way to share our love with our readers — who are certainly glued to the website, the App Store, and their iPhones, rather than out weaving a web of romance with someone special — than to underscore a few Valentine-savvy iPhone games?

Makeout Mania! from StormHatch ($0.99)

Makeout Mania! is a "chain-reaction puzzler" that puts you in the role of that love-spreading cherub, Cupid, on a mission to pierce the heart of a school full of unsuspecting students with your arrows of love, sending them on a frenzied bid to kiss, kiss, kiss, kiss.

The title offers 24 levels of gameplay in Puzzle Mode, where the mission is to pierce a heart and make the perfect match (consult the yearbook to see who's nuts about who) while avoiding the teachers at all cost. There's also Mania Mode where it's a race against the clock to trigger the most kisses possible in an ever-scrolling schoolhouse, with the option to compete against your Facebook and Plus+ friends.

Free, new levels are on the way and an update has been submitted that tweaks a few areas of gameplay.

App Store Link: Makeout Mania! ($0.99)

Flower Garden from SnappyTouch ($0.99)

A big part of Valentine's Day, for those of us that don't spend all our time playing iPhone games, is flowers. And, thanks to Noel Llopis of SnappyTouch, you can have your own lovely flower garden right inside your iPhone.

As we said in our initial review of the app, Flower Garden is not really a game. It does, however, fall into the same sim / virtual pet type experience that has boosted apps such as Koi Pond, Pocket God and Touch Pets Dogs to the heights of popularity in the App Store.

There's no real goal to Flower Garden. It's something of a zen-like experience, really. Grow flowers. Unlock new seeds. Clip flowers to make bouquets. And it's the last that really puts this game under the Valentine's Day crosshairs; you can make a lovely bouquet and email it to someone special. Basically, it turns your iPhone into a digital Cupid, with email for arrows. And, to make things even sweeter, the game is currently under a 60%-off weekend-only Valentine's Day sale at $0.99.

App Store Link: Flower Garden ($0.99, sale)

Whac-a-Mole: Whacky Valentines from Mattel (Free)

Everybody's played a whack-a-mole game, in one form or another. It's a pretty simple formula: the mole pops up out of its hole and you whack it.  And, who doesn't like to bludgeon moles? Especially when the damned things are trying to ruin Valentine's Day!

Whac-a-Mole: Whacky Valentines is basically a Valentine-themed version of the iPhone original [App Store] which is, as such games go, a pretty solid take on the whack-a-mole formula. Amusingly, the digital backboard of the game provides the occasional (though highly simplistic) mini-game — a nice touch.

I'd go into further description of the title but…it's free, so just download it and start whacking.

App Store Link: Whac-a-Mole: Whacky Valentines (Free)

Touch Pets Dogs Valentine's Goodies Pack from ngmoco ($2.99 DLC)

Virtual pet buffs need not be left out in the cold on this day of love and merriment. Ngmoco is currently offering a Valentine's Goodies Pack as paid in-game DLC ($2.99) in Touch Pets Dogs for those that want to lavish their v-pooch with as much love as can be.

App Store Link: Touch Pets Dogs (Free)

Happy Valentine's Day, everybody.

What do you get when you cross line drawing with a pack of hungry lions? Lion Pride [App Store], of course. As OpenFeint's free game of the day, you really don't want to miss this strange warthog munching simulator.

From our review:

The premise of the game is simple, you control a pack of lions and need to gather food for the rest of your pride. Thankfully, in this corner of the African savanna there seems to be a constant stream of warthogs, gazelles, and other beasts to munch on. Similar to Draw Race, you control the speed of the lions by how fast you draw lines from them on screen. Sneaking up on animals is important to keep them from running off, so you start by moving your lions slowly, then quickly go in for the kill. If something starts to get away, tapping twice on them will briefly stun them.

As you get further in to the game, you get more lions to control and tougher prey which needs to be attacked by multiple lions in order to be brought down. Lions need to be positioned to work as a team to all strike at once, and if any wandering hyenas come on screen they need to be scared off to prevent them from disrupting your food supply.

I really liked Lion Pride when we first took a look at it, and since then they've added additional game modes and all kinds of OpenFeint functionality to give the game tons of replay value through achievements and friends challenges. There's even fun facts about lions in game, how can you go wrong?

App Store Link: Lion Pride, Free (Today only.)

GTProductions, creators of the recently released 24 hour TouchArcade forum powered code fest, Super Ramen BROTHers is giving away their first iPhone game away for free today. Spring Fling [App Store] is a jumping game with a similar play style to Doodle Jump, but with the physics of a bouncing spring.

From our review:

GTProduction's Spring Fling is a jump-up-the-platform-wall game where you take on the role of a spring. Being a spring, it's not just a matter of tap to jump straight upward — you can compress the string and set the angle of your jump by way of a tap and drag mechanic. And the integrated PhysX engine makes the experience rather convincing. Choose an angle to shallow or severe and it's a platform miss with a plummet to your end.

Each jump uses up a supply of Power that doesn't get recharged until the next checkpoint. So, the game is a more deliberate physics/power management game than the fast paced action of other platform jumping titles.

Along the way rockets, balloons, parachutes, and pogo sticks help you scale the wall. The game includes five different worlds, some static and some downward scrolling. And achievements, online leaderboards, and Facebook / Twitter integration provide incentive to reach the highest height.

Spring Fling is free for a limited time, so if you're as much of a fan of these endless jumping games as we are, don't waste any time downloading this one.

App Store Link: SpringFling, Free (Today Only)

Little White Bear Studio's match-three puzzler Compression [App Store], normally $0.99, is free for today only. We took a look at Compression earlier this month and very much liked what we saw.

While the match-three space in the App Store couldn't be called anything but downright crowded, Compression manages to keep things interesting. You control blocks that drop from the top of the screen and attempt to match these blocks to the hollow pieces in order to get three of the same color in a column or row, which removes the pieces from the game board.

The twist in Compression's gameplay is in the walls, which move in closer and closer in a set pattern after every third piece is dropped into the board. A set of white dots appear on the section of the wall (either bottom, left, or right) that will compress inward next, so players can tailor their placement of blocks to best deal with the walls, which can remove blocks from the field if there is no more room for them after the board gets compressed.

In short, Compression just gets it right. The core gameplay is different enough to set it apart from the umpteen-million other match-three games on the App Store and simultaneously familiar enough that anyone can pick up the game and be relatively adept within minutes. Don't miss today's chance to grab the game for free.

App Store Link: Compression, Free (today)

Mobile Bros' puzzle platformer Trundle [App Store] was released yesterday, and is getting nowhere near the attention it deserves. Trundle is a free game with a neat art style all tied together with simple tilt and touch controls that create a great (but short) gameplay experience.

The object of the game is to simply roll a black ball from one side of the screen to the other. Tilting the phone controls your movement, and tapping on the screen jumps. Along the way you'll come across different vehicles to ride in, switches to activate, platforms to navigate, and other obstacles that often have different physics-based challenges to overcome.

Trundle itself is rather short, and shouldn't take you much more than an hour to finish. However, the iTunes description mentions additional level packs available in the future via an in-game purchase. I had a lot of fun playing through the game, and I think this kind of DLC model is great, especially since the amount of content in Trundle doesn't make the game feel like a demo at all.

The few people who have downloaded the game already in our forums are really enjoying it so far, and I doubt I'm alone in hoping they hurry it up with the additional level packs.

App Store Link: Trundle, Free