A minute into Radiant Flux and the first thing that you wonder is how a game from 1985 can have possibly remained unpublished for so long?

The second thing is probably going to be something so unsavoury we can't publish it here, thanks largely to the game's unforgiving difficulty level.

Of course, Radiant Flux isn't really from 1985 - it just thinks it is. The deliberately humble visuals are a throwback to the days when the ZX Spectrum and C64 were the tools of choice for any serious gamer, and this title does an excellent job of imitating the best shooters of that era - in a purely visual sense, at least.

Back to the future

Sadly, the stern difficulty level isn't a figment of your imagination. Nor are the slightly clunky controls, which are based entirely around the D-pad and face buttons - despite the fact that the game's 360-degree movement would have been perfectly suited to a twin-stick analogue control method.

Radiant Flux is unusual in that the playing area scrolls from right to left, with enemies attacking from all directions. Your ship can move in eight directions but it can only fire up, down, left, and right - a restriction that leads to many annoying deaths.

Thankfully, you can also lay mines and launch smart bombs, allowing you to extract yourself from several sticky situations.

Trigger happy

Ultimately, though, Radiant Flux becomes so incredibly taxing that it's almost certain to dishearten anyone who doesn't consider themselves to be a seasoned shooter pro.

The difficulty becomes almost sadistic on later levels, where you're not only having to avoid the unwanted attentions of your enemies but also to pilot your fragile ship around environmental hazards.

Radiant Flux's 8-bit graphics - complete with a cool hazing effect when you take damage - are unquestionably its biggest highlight. The single piece of music - which loops constantly - is also infectious and catchy, but the presentation isn't enough to atone for the game's other shortcomings.

Retro shooter addicts will appreciate the homage, but for everyone else there are better things on PlayStation Mobile to spend your pennies on.