On its official website, British developer Puppy Games declares Titan Attacks as 'the best Space Invaders tribute ever'. Whether you choose to agree with it or not, this simple statement aptly describes what to expect from this homage to Taito's 1978 classic arcade hit. Yes, it's time to jump into a somewhat impractical tank in order to save the Earth from an invading alien army. Armed with a cannon and locked into a plane of horizontal movement across the bottom of the screen, your objective is to eradicate all incoming waves of enemies by blasting them into pixel oblivion.

The initial wave is all too familiar; a bunch of hapless invaders plod slowly in formation across the sky, begging to be shot to pieces. Additional features soon materialise, however - avoid taking any hits to activate a multiplier that increases with each wave passed unscathed, maxing out at x9; taking damage resets the multiplier back to zero. Growing this multiplier doesn't just boost your score, but also increases the amount of 'bounty money' you gain from each destroyed alien.

After each wave a shop becomes available, selling helpful items in exchange for your hard earned cash. Consumable items such as smart bombs and additional shields are available as well as permanent weapon upgrades and additional firepower. Increasing prices (the shopkeeper clearly favours profit over saving the planet) forces a strategy of deciding your preferred upgrade path. Will you aim for a more powerful gun to cut through the tougher, later enemies, or save up for a second side mounted gun?

Further progression sees the enemy adopt new attack patterns; spinning, teleporting and swooping low in an attempt to reduce your shield to zero and force a game over. There are a few other gameplay flourishes, such as high flying UFOs that provide random bonuses such as additional points, money or a short-lived burst of additional weaponry. Destroyed aliens might kamikaze spin down to earth instead of exploding, and shooting them in this state gains extra points. Parachuted aliens sometimes choose to eject from their doomed spacecraft; you can catch them to earn extra cash, but allow any to land and incur a penalty. Assessing whether it's worth attempting a catch or forfeiting in order to keep your shield intact becomes a regular decision in later waves.

There are a total of a hundred waves to complete, with the backdrop changing after every twenty. Each different battleground represents a location - Earth, the Moon, Mars, Saturn and finally the aliens' home planet of Titan. There's a rather uninspired boss battle at the end of each, plus a few bonus rounds scattered throughout which involve shooting a set number of swiftly moving UFO's for more goodies. Progression is saved in planetary chunks, so you can begin from any completed location or save and quit at any point to pick up exactly where you left off.

Complete all waves and everything begins anew from the beginning, only this time it's a little tougher and thankfully all your upgrades remain intact. After this point, death is final; there are no more planetary checkpoints, this is purely for high score chasing. There's an online leaderboard to climb for bragging rights, which fast becomes the only real incentive to keep playing.

In fact, once you've cleared the game once or twice it becomes apparent there's not an awful lot else to do. In later waves, simply purchasing and using smart bombs allows wave clearance in seconds, plus once you have acquired a decent set of additional firepower most of the challenge is removed. This isn't helped by the ease at which you can refill your shield to maximum in the shop, further decreasing the skill requirements for those with sharp skills.

Previous releases of Titan Attacks on rival platforms benefited from HD resolution graphics, meanwhile, bringing the retro-inspired designs to life with vibrant colour. Unfortunately on the lower resolution screen of the Nintendo 3DS this effect is lacking, and the visuals come across as muted and dulled down; there's also no stereoscopic 3D (all action is on the top screen) and some slowdown in busier moments. Considering this is a game that was originally released over 3 years ago on PC, it's a shame to see this latest iteration arrive with no new additions and less overall polish.

Conclusion

There is fun to be had in Titan Attacks while it lasts, but with a fairly high entry price (at the time of review) it's reasonable to hope for a little more content and polish - a competent player will easily see everything on offer in just a few hours play. Unless you happen to be a traditional arcade player who is willing to spend days chasing high scores through repetition, this probably isn't the game for you. If you are in the market for a single screen, space-based 'shmup' you may - in addition - want to consider the NES version of Galaga, which is also available on eShop. It's a tougher challenge, and arguably trumps even the mighty Space Invaders. Ooh, controversial…