Free iPhone and iPad games: Pictorial HD, Lost Underworld HD - Great Adventure!, Alpha Command

Welcome to our mid-week edition of Pocket Gamer's free game round-up - a feature that highlights the top App Store titles that have been made free in the past 24 hours.

In case you're still unaware, prices in the App Store are constantly changing. Grab these freebies quickly or you may miss out on them.

Remember: let us and your fellow readers know about any other great free apps in our comments section below.

And go here to find the latest App Store updates, price drops, and more.

Pictorial HD is an iPhone puzzler that tests your spatial reasoning by asking you to uncover pictures hidden in a sky of stars, a snow storm, and more.

Apple's Game Center is on board with a bevy of achievements for you to proudly display.

Download Pictorial HD

Your aim in Lost Underworld HD - Great Adventure! is to successfully navigate dangerous obstacles, break your way through the earth's crust, and escape to freedom using a range of different vehicles.

If you want to - once again - see the light of day, you'll have to overcome scary spiders, bats, man-eating flowers, and much more.

Download Lost Underworld HD - Great Adventure!

Alpha Command (iPad)

Alpha Command is a Space Invaders-esque shooter with a twist. To destroy your incoming foes, you first have to match their colour by tapping the several panels that litter the bottom of your iPad's screen.

There are over 60 different achievements to unlock as you play, and a series of leaderboards to tackle.

Download Alpha Command