Friday £5 - Super Crossfire, Squids, Siegecraft, and Scribblenauts Remix

We're a bunch of cheapskates at Pocket Gamer. You wouldn't know it with our flash cars and diamond-studded iPads, but when it comes to the App Store we'll wince at anything over 69p and will need to sleep on any big purchase for about a week.

So we decided to funnel this frugality into a feature. It's called The Friday £5. Each week I'm given a crinkly green piece of paper to spend on downloads from iTunes. We're looking for value for money, lots of re-playability, and cheap cheap prices.

This week we get all that in games like Squids, Siegecraft, and Super Crossfire, which all have one thing in common: they start with the letter S. Wait, no. They are all addictive, long-lasting, and will sit on your homescreen for weeks.

Super Crossfire
iPhone - 69p / iPad - £1.99 - Chillingo

Xbox Live Indie developer Radiangames - now an iOS refugee - pegs Super Crossfire as the "next evolution in the arcade shooter genre". Well it certainly knows its genetic ancestry, cribbing ideas from the ancient roots of Space Invaders to the brutal bullet-hell shmups from Cave.

But the game has its fair share of unique ideas, too. Your zippy on-tracks turret can warp from top to bottom, effectively flanking the crowd of enemy spaceships - who dutifully spawn in waves, in the middle of the screen - until they spin around to return fire.

The game also packs a comprehensive upgrade system, which lets you switch and swap parts of your spaceship to augment it in ten different areas. And you'll need to when going toe-to-toe with 19 different types of enemies with unique behaviors, attack patterns, and attributes.

Super Crossfire is fast-paced, intensive stuff, backed by a pulsing soundtrack and drenched in neon visuals. Trudging through 150 waves of nasties is fun by itself, but get locked into a high-score battle on Game Center and the title's true addictive nature will show.

Scribblenauts Remix
Universal - £2.99 - Warner Bros

The concept behind Scribblenauts is so mind-bendingly unbelievable that it almost begs to be downloaded just to make sure we're not lying to you. You see Maxwell, the game's springy-limbed hero, has a magical notebook where any object you spell out will magically poof into existence.

Tap out "dinosaur", and a toothy green reptile appears. Spell "atomic bomb" and a colossal missile will fall out of the sky and wipe out everything on the screen. Adjectives work, too, letting you make a shy cat or a wet rasher of bacon. Roughly 30,000 nouns are present and accounted for, letting you spawn anything from God to Tom Jones.

Sadly, the 50 included puzzles rarely require you to stretch your brain box and tap into your imagination cortex. A lot are just cryptic challenges (create five objects you'd see in a school!), asking you to figure out exactly what the level designer wanted. But when you're given free rein, everything comes together splendidly.

Remix borrows 40 stages from the DS originals, and has ten stages that are exclusive to this universal iOS version. There's no level editor, which is a shame, but the £3 entry fee is well worth it to see a fire-breathing hamster roast a shy goose.

Squids
iPhone - 69p - The Game Bakers

French newcomer The Game Bakers has hit the App Store running (or, more accurately, swimming) with its debut title: the cute and creative fling-'em-up strategy epic Squids.

You command an army of cephalopod troops who are waging war on some yucky ocean pollution. To fight back you'll need to grab four different types of squid - shooters, scouts, troopers, and healers - stretch them back like slingshots, and then fire their slimy bodies at nearby enemies.

It's a turn-based, tactical affair, so you'll need to take stats like strength and movement into consideration before making your move. You'll also want to dodge enemies and pick up items like hats - for armour - and stars - for a points boost - too.

All in all, it plays like the slimy underwater lovechild of a stat-swapping strategy game and a physics-focused slingshot app. As a curious blend of two very disparate genres, it's a miracle that it even works, let alone that it's enormous, Silver Award-winning, fun.

Siegecraft
Universal - 69p - Crescent Moon Games

It's starting to feel like we highlight a new tower defence game with a difference just about every other week. But outside match-three puzzlers and games with "Angry" in the name, defending a castle from endless waves of goons remains one of the most popular genres on iOS.

Siegecraft, the result of a creative collaboration between Crescent Moon Games and Blowfish Studios, is a tower defence game with - you guessed it - a difference. While you'll drop down turrets to take out incoming nasties you'll actually go hands on with the weapons.

You can't sit back and wait for your defences to take out enemies. Instead, you'll need to leap into the fray, twinging turrets and pulling back catapults to end your attackers. It's a little like Angry Birds, but top-down and in defence of marching badnicks. Fewer birds, too.

It's got 25 levels to play through, in five different campaigns, and multiplayer. Thanks to Game Center's new asynchronous turn-taking you can play with friends around the world at your own pace. And, on iPad, it lets you go head-to-head on the same screen.