This week has seen a number of excellent and much publicized and high profile releases -- Rockstar's conversion of Grand Theft Auto: Chinatown Wars from DS to PSP and Gearbox's post-apocalyptic co-op sandbox shooter Borderlands -- but no game has eaten as much of my time this week than a downsized iPhone version of a rhythm favorite. Rock Band [Harmonix/EA Mobile, iPhone] EA Mobile's downsized port of Harmonix's rhythm-standard enters an App Store dominated by clones and competitors (the Tap Tap series chief among them), and what sets Rock Band apart from the rest is a subtle but massively important distinction. With Harmonix's access to a staggeringly large library of original masters, the iPhone game is able to do what none of the others can: make the music itself reactive to your play. By comparison, Tap Tap plays as a transparent overlay on top of any given track: keep your hands away from the screen and the music cheerily plays on, unperturbed by your quiet failing. That Rock Band gives you its now embarrassingly too-familiar skronk on every missed note is key to sustaining the illusion that you're participating in the performance, even just by slapping a thumb onto a glass sheet. The iPhone version, unlike Rock Band Unplugged -- Backbone's similarly excellent PSP version released a few months back -- only lets you play one instrument or vocal track at a time, which allows for RB's least publicized and surprisingly well implemented feature: in the absence of three additional people to play its Bluetooth-enabled local multiplayer, players can send out invites to Facebook friends to participate in asynchronous "band" play. With it, each of the 2-4 players complete their individual instrument on their own time, submitting their score back to the 'band' afterward, at which time a total score and fan-increase is tallied and push-notification submitted back to each, making you feel far more connected than you would expect from such an otherwise solitary game. Losing the plastic-instrument charade might at first seem a down-step too far for more casual players, but with its promise of a continually refreshed music library (its in-app music store already includes six two-packs of add-on tracks), Rock Band is a long, long overdue and essential musical addition to the App Store. Small Worlds [David Shute, web] The week's other best surprise -- going off indie-circle buzz -- is David Shute's Small Worlds, a Flash game entered into the Casual Gameplay Design Competition hosted by free/web powerhouse site JayIsGames. Like so many indie efforts, the less said about the game up front the better: this CGDC's theme was 'Explore', and it's the play on exploration that makes Worlds so unique. Know, at least, that what it does best is take the iron-grip compulsion to 100% map screens in exploratory games like Castlevania: Symphony of the Night or Metroid and bring it directly to the fore of the game itself, making it its own reward. If this seems too frustratingly vague, it's because the Small Worlds experience is short, sweet, and immediately available: don't miss carving out some 20 minutes of your weekend for it. Eufloria [Rudolf Kremers & Alex May, PC] Elsewhere, Rudolf Kremers and Alex May have finally released their Indie Games Festival finalist Eufloria, formerly known as Dyson. As you can see above, it's a game that'll feel familiar to any iPhone gamer that's taken part in the arcade-strategy planetary invasions of Galcon, but with a fantastically gorgeous ambient score (courtesy Brian 'Milieu' Grainger) and visual design that soothes you into and through its dizzying floral battles, it's truly in a league of its own. Find it either via the official homepage, or through its Steam release. LostWinds: Winter of the Melodias [Frontier, Wii] Frontier's platformer LostWinds marked the stateside debut of Nintendo's console downloadable service WiiWare, and its long-awaited sequel also marks the services 100th release, and arguably remains the best exclusive the service has to offer (sitting happily alongside 2D Boy's World of Goo and Gaijin's BIT.TRIP series). Still unrivaled in its split approach to Wii-mote and joystick play, the game gives you both direct control over its vulnerable child-hero Toku, who's helped through his journey by Enril, a spirit of the wind, here represented by the flourishes of your Wii Remote. Its Melodias sequel brings every bit of the quiet charm of the original, and adds new seasonal powers giving you the ability to turn frozen ponds to deep-diving pools and a 'cyclone' ability to help puzzle your way further into its world and should be on top of the weekend download list for any Wii owner. Space Invaders Extreme 2 [Taito, DS] Finally, this week also saw the stateside release of another highly anticipated follow-up with Space Invaders Extreme 2: Taito's retro-futurist re-imagining of its arcade classic, still one of the finest reworkings in game history (edging out even their own masterful iPhone re-invention Space Invaders Infinity Gene). Following down the same disco-dance road as Q Entertainment's cult-classic Rez, Invaders Extreme is classic play done up in techno-rave clothes, each shot contributing to the deep-thumping remix beat that runs underneath. Its sequel adds the still perplexingly devised 'Bingo mode', and remains as essential an experience as the first.