iPad reviews of the week: Shantae: Risky's Revenge, ProtoSlice, Sad Robot, Brothers in Arms 2: Global Front Free+

It wasn't planned out this way (seriously), but all four games this week are free downloads; aside from ProtoSlice HD – which has a separate iPhone release – they're universal apps, as well. Granted, one of the titles requires an in-app purchase to access the entire game, while another utilizes in-app investments to buy ammunition and replay failed stages without a lengthy wait. It's a brave new world of free-to-play iOS experiences, and we're smack dab in the middle of it this week.

Game: Shantae: Risky's Revenge
Price: Free ($4.99/£2.99)
Size: 95.6MB
Buy it now from the iTunes store: US / UK

We're big fans of Shantae: Risky's Revenge here at GamesRadar – which may not surprise you, given the sparkling 9 we bestowed upon the original DSiWare version last fall, and its inclusion on our list of 10 essential DSiWare games for 3DS owners. In the review, we called the sequel to the overlooked Game Boy Color classic a "perfect platformer" and "proof that the 2D side-scrolling formula still holds up after all these years." As such, the release of a universal iOS release begs not the query of whether it's a good game – we know that – but rather if it's a worthwhile port.

Luckily, that's mostly the case here, though we'd hesitate to call Shantae: Risky's Revenge a fully optimized port for iPad. In execution, it mostly looks like a blown-up version of the DSiWare original, which means the well-animated pixels look a bit chunky on the tablet screen, but still maintain a retro-like charm. The one big upgrade here is that conversational sequences depict large character drawings instead of sprites – though, admittedly, we would've loved to see the entire game bumped up to such a glossy standard. And as expected for a precise platformer, the touch-based controls aren't quite as successful – especially due to a twitchy virtual stick that causes occasional consternation.

As such, we can't help but still dub the original DSiWare release the optimal version of the game, but Risky's Revenge still warrants a strong look on iPad and iPhone – not only because it opens up the game to a much wider audience, but also due to the much lower price. While the app arrives as a free download (with a demo version in tow), you'll pay $4.99 to access the entire game – but that's still less than half the price you'll pay on a Nintendo DSi or 3DS. Shantae: Risky's Revenge is an excellent retro-influenced platformer no matter how you cut it, and a couple touchscreen concessions certainly don't ruin the fun here.

Game: ProtoSlice HD
Price: Free
Size: 31.5MB
Buy it now from the iTunes store: US / UK

Aside from Geometry Wars Touch and Call of Duty: Zombies HD, Activision has kept pretty quiet on the iPad front – which is surprising, considering how many of its properties could easily make the jump to the tablet (especially those with existing iPhone iterations). ProtoSlice HD seemingly marks the debut of open-world action hit Prototype on the platform, but that's not entirely true. In fact, it's a promotional game: just an elaborate marketing tool meant to draw up a little buzz for next spring's sequel. But it's free – and actually a re-skinned version of an existing iPad puzzler.

Slice HD – which gets shout-outs on the menu screens – is the original app in question, and ProtoSlice HD expectedly follows a similar routine as that recent release. Each puzzle begins with a series of blades (like those jutting from the main character's arm) on screen, which conveniently cover up buttons that display Prototype 2's logo. It's your goal to remove the blades from view in the proper order long enough to touch the button, but swiping your finger against the sharp end of a blade fills the screen with blood and ends your quest. While amusingly gruesome, it's not just a gimmick meant solely for shock value: it actually takes some skill to navigate these puzzles, not to mention nimble fingers.

Granted, ProtoSlice HD is still a big, obvious promotional tool for the upcoming console game, and the app never lets you forget it, thanks to between-level screenshots of the game and a big link to the trailer. Anyone with a weak stomach for in-your-face marketing might want to pass, but ProtoSlice HD is worth the look for anyone intrigued by the premise of avoiding and arranging digital blades to solve puzzles. It's actually a pretty great demonstration of multi-touch tech, and it's not like the app costs you anything. Well, besides a small shred of dignity.

On the next page we'll look at two more games...