Invedars has Hidden Doodles (iTunes Link) for the iPhone, iPod Touch, and iPad in the iTunes App Store for FREE (regularly 99-cents) for a limited time.

Train your memory playing in this awesome “hidden objects” game.

Pangea Software, Inc has Enigmo (iTunes Link) and Enigmo 2 (iTunes Link) for the iPhone and iPod Touch and Enigmo Deluxe (iTunes Link) and Enigmo 2 (iTunes Link) for the iPad in the iTunes App Store for FREE (regularly $2.99 each) for a limited time.

Enigmo is a 3D puzzle game where you direct animated streams of flowing liquid so that the droplets get to their destination. Water, Oil, and Lava fall from Droppers and bounce around the walls of the puzzle. You move and rotate various types of bumpers, sliders, accelerators, and sponges in order to divert the flow of the falling droplets. The faster you complete each of the 50 levels, the more bonus points you receive. In addition to the 50 levels that come with the game, you can also download many more levels for free created by other users.

Enigmo Deluxe offers all the same features as the original for the iPad, plus enhancements like a built-in Level Editor which lets you create, edit, and play your own levels, over a dozen free additional Level, and an entirely new music soundtrack composed acclaimed Spanish guitarist Stefan Schyga.

Enigmo 2 is the successor to our award winning puzzle game, Enigmo. There are streams of falling water droplets, plasma and laser beams, and your goal is to get them into their container by using the various puzzle piece that you are given. Enigmo 2 goes to a new dimension as the puzzles are now three-dimensional! We’ve also added tons of new gameplay elements including lasers, plasma, gravetoids, teleporters, gravity inverters, etc. There are 50 all new levels in Enigmo 2, and an awesome music soundtrack! Enigmo 2 also adds the ability to play in true HD on your HDTV via Airplay on iOS 5 or higher!