Welcome to this week’s edition of iPhone + iPad Gems! Today, we’re looking at three budget games from the App Store, including one universal iPad/iPhone/iPod touch title with high-resolution graphic support on all three devices, an iPad-specific game, and an iPhone/iPod touch-specific title that runs in upscaled mode on the iPad.

Our top pick of the bunch is Infinity Field, but all three games are worthy of at least our general-level recommendation. Read on for all the details.

Can Knockdown 2

Forgettable ideas can be transformed into impressive games by impressive execution. Infinite Dreams’ Can Knockdown 2 ($1, version 1.01) demonstrates exactly how this works: it is literally nothing more than Angry Birds on a different angle—first-person rather than side-scrolling—and without the funny animals. You use swipe gestures to toss balls at cans and other targets, moving from level to level by clearing everything from the screen. The primary mode involves knocking down sets of increasingly challenging but stationary cans, while others have pop-up wooden bullseyes and/or moving cans of various sizes instead. Each mode gives you a limitation, either in balls or time, that can be extended through proper play; otherwise, your game ends after a minute or two. That there’s nothing deeper here, such as a save game feature with a hundred levels, or different ball physics a la Angry Birds’ projectiles, is the biggest knock against this game.

But what Can Knockdown 2 offers as a reward to players is a graphics engine that makes outstanding use of the Retina Displays on new iPhones and iPod touches, as well as the full 9.7” screens of iPads. The 3-D balls, 3-D cans, and 2-D but animated backdrops are so impressively detailed and plausible that they could be mistaken for photorealistic; Infinite Dreams includes smoke plumes, shadows, and other little effects to spice up the scenes, too. Music is left out in favor of ambient sound effects that work with the art to provide urban grit; there could obviously be more and better audio, but what’s here suffices for a $1 game.

Can Knockdown 2 reaches its apex of challenge during the moving can levels, which force you to consider not just where the target is, but where it will be when your ball arrives. Learning to control the speed of your ball tosses isn’t easy—a practice mode would be great—but you effectively practice as you replay the levels. Unlike Angry Birds, the fact that you can alter the speed and/or power of a shot isn’t obvious from any sort of dotted line indicator; it’s just something you come to discover on your own. Can Knockdown 2 initially rewards this knowledge merely by letting you continue to play, then introduces bonus items; the moving can mode for instance brings up a wider variety of targets that can explode in different ways, slowing down or speeding up time, adding bonus points, and more.

In as much as the App Store now offers “full” games and bite-sized “casual” ones that aren’t going to set the world on fire but provide ample entertainment for their low prices, Can Knockdown 2 is clearly in the latter category—just an Angry Birds appeared to be prior to its post-release updates that added levels and improved its value. Thanks as much to its graphics engine and art as its familiar but fun gameplay, Infinite Dreams has the makings of a similar phenomenon on its hands here. With a little extra content and charm, Can Knockdown 2 could become as big of a deal as Rovio’s title. iLounge Rating: B+.

Infinity Field

While it would be fair to call Chillingo’s Infinity Field ($2, version 1.0.1) a clone of Activision’s Geometry Wars: Touch, there’s no doubt that what developer ForzeField Studios has accomplished with this title is thrilling enough to justify downloading on its own merits. As with Geometry Wars and earlier, similar iOS titles, Infinity Field gives you two virtual joysticks to separately control the movement and shooting of a spaceship trapped in a box with hordes of single-colored enemies. Survival mode lets you play for as long as you can survive with three lives, with six separate initially selectable scenarios, and Campaign mode offers roughly 50 levels to play through in sequence, generally requiring you to remain alive for 90 seconds per level as more and more enemies drop into the play area.

While this will all sound pretty familiar to Geometry Wars fans, and the glowing vector/line-based graphics with a pulsating background grid has plenty in common visually with Activision’s game, Infinity Field offers a lot of individual fun for the $2 asking price. The intensity of the line and particle artwork is increased by four different camera views, two of them with 3-D tilting and camera panning, guaranteeing that the screen will be filled with explosions and glow effects almost all the time. Floating power-ups offer temporary force fields, slow motion action, and occasionally even screen-clearing bombs, though the latter weapon is far less common here than in Geometry Wars. Chillingo instead uses other interesting gameplay tricks, such as levels that remove your gun in favor of Tilt to Live-style limited-area explosions, to keep the stages challenging. Boss encounters come every dozen levels, and are worth seeing. The virtual controls are responsive throughout, aided by the iPad’s extra screen real estate.

Infinity Field’s only major issues are generally forgivable for the low price. The in-game song is close to great, but doesn’t change—it just keeps playing level after level, without any sort of voice or other special audio effects to elevate the game’s sounds above “good.” An in-game ship upgrade system is at best confusingly implemented, using a system to acquire currency that isn’t anywhere near as obvious as it should be, though the occasional opportunity to boost your guns is entirely welcome. And multiplayer features are presently half-baked; there’s a split-screen way to play the Survival levels, with a wi-fi mode that’s listed as “Coming Soon.” While what’s here is better than nothing, it’s obvious that the game is unfinished, though many companies would have considered it complete enough for $2.

Despite the flaws, Infinity Field is a great game for the price—a better value for $2 than Geometry Wars: Touch was when it originally debuted for $10, if not quite as original. It’s currently an iPad-only release and very acceptably priced as such; hopefully iPhone and iPod touch support will be added alongside the multiplayer mode in the near future. iLounge Rating: A-.

Tiny Wings

While it would be unfair to write off the shocking success of Andreas Illiger’s recently-released iPhone and iPod touch title Tiny Wings ($1) as traceable merely to the combination of a happy bird theme, simple “casual” gameplay, and a low price point, we’re convinced that these elements have a lot to do with its rapid ascent to the top of the App Store’s charts. Tiny Wings has a lot in common with 2009’s Canabalt and 2010’s Solipskier, both one-trick-pony casual action games that rely upon the perpetual motion of a jumping main character to keep you focused on the screen. Appropriately, Canabalt was black-and-white, Solipskier added splashes of color to a largely black and white world, and Tiny Wings brings full-colored pastels and softer edges to the table, effectively gender-neutralizing or feminizing previously popular guys’ game concepts to appeal to a larger potential audience.

The gameplay in Tiny Wings is almost as simple as can be. You proceed from “island” to “island,” using a single button—almost anywhere on the screen—to exert the force of gravity on a bird whose wings are only capable of the most limited flight. Holding the button down brings the bird towards the ground like a rock, while not holding it down enables the bird to alternate between riding soft hills and catching air in little skips. Your major challenge is to figure out how to properly time button presses to build up the bird’s speed on the ground so that the jumps become larger. Simply continuing to make progress earns you points, while coins can be gathered by riding certain hills, and huge “cloudtouch” jumps are available when you figure out how to catch the maximum air through momentum.

Tiny Wings is most impressive in aesthetics. Both the soft visuals and the gentle music feel breezy and confident, mixing an upbeat single song and “keep moving” pacing of an early Sonic the Hedgehog game with the dreamy, almost storybook cutout looks of Nintendo’s 1990’s Super Mario/Yoshi’s Island games. Everything moves at a smooth frame rate—60 frames per second—and there are no rough edges to be seen in any of the art; everything’s curved and soft, though sadly without high-resolution iPad support. That aside, this is a thoroughly happy game that kids and parents alike can play, contrasting heavily with the gritty pixels and deliberately high-contrast colors in titles such as Canabalt and Solipskier.

Our major issue with Tiny Wings is one that seemingly hasn’t stopped similar games from being successful in the App Store: the gameplay is a one-trick pony, and relies upon the now well-worn “beat your high score” challenge to keep you playing. This isn’t to say that the levels aren’t challenging, or that the experience isn’t fun for a while, but it’s not very deep—there’s not a huge amount of variation in the hills or the action. You have one life per game, and need to restart from the beginning whenever day turns to night, which happens faster if you slow down on an island. The developer keeps the levels interesting by changing the artwork procedurally—through a limited collection of patterns, colors, and hillside graphic elements—each day, but that’s no substitute for greater depth.

Thanks far more to execution than to gameplay concept, Tiny Wings delivers just enough fun and charm to be worthy of the $1 asking price, but not much more than that. As compared with the other games in Gems today, it delivers a considerably more shallow experience, but one that’s more likely to leave you with a warm heart after your first or second play. Whether you continue to come back to it for more depends on how much you’re incentivized by high scores and simple artwork changes. iLounge Rating: B+.