So, is it possible to fit another worthy line-drawing game into an already crowded market? Backflip Studios thinks so with their new game Harbor Havoc 3D [$1.99].

Like Flight Control, the objective of the game is to route your ships to their proper docks. Simply draw a line from the ship to the dock and you're on your way. Harbor Havoc 3D's claim to fame, however, is the incorporation of multiple layers of vessels that you must properly navigate. Depending on the map, this can include submarines, boats and helicopters or even submarines and ground rovers in the underwater map. Each type of ship can only collide with like ships, so keeping this in mind is critical for success.

The game comes with 4 maps: Far East, Atlantis, Arctic, and Lighthouse. Each offers a variant in gameplay. Far East is your straightforward Flight Control setup where you are docking different ships to their ports. Ships, however, don't have to be undocked as in Harbor Master. The game also adds an anchoring mechanism by tapping on a ship that will keep them in place. The Far East map is going to feel boring to anyone who has put in much time in any of the existing line-drawing games, but Atlantis and especially Arctic are where things get interesting.

The developer's gameplay video shows how crazy things can get and even shows the locked Lighthouse level which gives you a partially obscured view of the play area.

For advanced players who have gotten bored of Flight Control and are looking for more of a challenge, Harbor Havoc 3D manages to provide added layers of challenge without necessarily being different just for the sake of being different.

App Store Link: Harbor Havoc 3D, $1.99

Everyone loves a freebie! If you don't already own these four games, their respective developers recently released lite versions for you to whet your appetite before jumping in to the full version:

Lion Pride Lite, Free (Lion Pride, 99¢) – A neat spin on line drawing games, Lion Pride has you taking control of lions and chowing down on the various prey of the African wild. Utilizing a Draw Race-like system where the speed of the line you're drawing determines how fast you move, Lion Pride is a great addition to the somewhat crowded line drawing genre. We enjoyed the full game in our review, and Lion Pride Lite is really worth checking out.

Uno Free, Free (Uno, $4.99) – What even needs to be said about this? If you've ever played the XBOX Live Arcade version of the game, the iPhone version is very similar. If you haven't, just imagine the classic game of Uno playable against AI opponents as well as friends or complete strangers online, all without needing to carry around a deck of Uno cards.

Dungeon Defense Lite, Free (Dungeon Defense, 99¢) – Dungeon Defense is similar to a tower defense game, except instead of building towers you position guards in a number of predetermined points on the map. You have a variety of units that can be placed such as swordsmen, archers, or axemen, and you need to fend off waves of attackers. The lite is worth checking out if you're a fan of the tower defense genre.

NFL 2010 Free, Free (NFL 2010, $2.99) – If you're looking to find out how a full-on football game works on the iPhone, give NFL 2010 Lite a try. We thought NFL 2010 was impressive in our review, but since then, Madden NFL 10 has also been released. Gameloft has attempted to make the decision between which game to get a little easier, recently dropping the price of the full version to $2.99.

Drawing games are becoming more and more popular, and for good reason. Out of all the different control methods on the iPhone, few are more natural than simply drawing on the screen.

Draw Race [App Store] takes a unique approach on racing games. Employing the familiar drawing mechanic, you literally draw your racing line around the track. The speed of your finger controls how fast or slow you go and once the race starts your car tries as hard as it can to stay on the line.

If you draw too fast around a corner your car can spin out so there is a small skill curve to the game as you get a feel for how fast you need to draw compared to the handling capabilities of your car. Currently included in the game are 20 tracks, and once you complete a race in the single player mode you'll be able to race other people online and compete in time trials.

The developer released the following trailer:

Flyloop [App Store] utilizes a similar drawing mechanic, only this time you're drawing circles around butterflies to catch them as they fly across the screen.

What initially appears as a tranquil game of catching butterflies in a field quickly escalates in to frantically drawing circles trying to match pairs. The game has an acoustic guitar soundtrack, and global high scores if you're in to that kind of thing.

Watch the trailer for Flyloop to see it in action:

Both of these games use screen drawing in different ways to create entirely different gameplay experiences. Draw Race and Flyloop are both worth checking out if you want a couple of simple fun games without needing to use virtual D-pads or tilt controls.

App Store Link: Draw Race, 99¢ – Flyloop, 99¢