Nobody ever said being an astronaut is easy. Unfortunately for the eponymous hero of Nexus Game Studio’s Gravonaut (Out now, $.99), his or her problems are just beginning when the lunar lander touches down. Once the spacecraft starts exploding for mysterious reasons the Gravonaut reacts sensibly enough by running like there’s no tomorrow, but whatever targeted his or her ship has made things even more dicey by littering the path of escape with deadly spikes, lasers, zombies, giant space worms, and more! It’s up to the player to use the Gravonaut’s penchant for manipulating gravity to make it past one deathtrap after another.

There’s no health meter in Gravonaut. There are no checkpoints to continue levels midway through. There’s no “easy” mode — in fact, the difficulties on offer range from “Hard” to “Hardest.” There are no hand-holding tutorials. There’s just the nerve-wracking pop of the Gravonaut’s pressurized spacesuit the moment it gets zapped or pricked open by environmental obstacles, and those moments crop up with a frequency sure to unsettle even hard-boiled gaming veterans.

Mixing 2D sidescrolling with a touch of physics puzzling, this topsy-turvy platformer tasks the player with toggling the Gravonaut’s antigravity boots on and off using two virtual buttons at precisely the right moments. The Gravonaut’s movement otherwise falls outside player control, and any ill-timed gravity reversal will send the Gravonaut careening helplessly toward certain doom. The main game contains fifteen levels and while these are mercifully short at first, Gravonaut ratchets up the challenge with longer, more complex routes that leave progressively less room for error. The major difference between difficulty levels is simply how many curse words the player will feel compelled to launch at his or her iDevice within a given amount of time, as these alter the rate at which the Gravonaut runs.

A game that demands perfect player performance must meet its audience halfway with an equally flawless interface and in-game physics, and thankfully Gravonaut succeeds here. I found Gravonaut‘s physics consistent – if sternly demanding of attention to its intricacies – and its interface as reliable as it is simple. The game rewards stellar performance with unlockable characters (a zombie-naut and an alien, for example), but sadly these appear to be mere costume changes with no noticeable game-changing impact. Gravonaut does follow up a successfully finished main game with two additional modes to keep the challenge hot and heavy for any player brave enough to stick with it.

Gravonaut allows external music to be played over its sound effects via its main options menu. On the one hand its default music consists of the blips and bloops one might anticipate given its unabashedly ancient aesthetic, but on the other hand they’re unobtrusive enough to complement Gravonaut‘s retro visuals without making the player’s ears bleed.

An important note: Gravonaut requires a 3G or 4G iDevice as of this review.

iFanzine Verdict: While the faint of heart need not apply, Gravonaut does a superb job of putting a twist on the traditional platformer and handily accomplishes its stated goal of being one of the most difficult videogames in existence. The fact that it sticks to this premise so well inherently limits its appeal, but if you’re a true challenge seeker looking for your next retro-style fix, Gravonaut is an excellent App Store entry to spend a buck on.