Imagine you wander into your local retro game store and happen across a system you've never heard of before, produced by a company whose name is equally unknown – and then you discover that there are 50 games available for this platform, covering genres such as action, adventure, puzzle, fighting, platforming, sports, RPG and shmup. Then imagine that every one of these 50 games is addictive and engrossing – that effectively comes close to explaining the joy of UFO 50.

Produced by a team of indie developers (led by Derek Yu) with hits like Spelunky, Downwell, Skorpulac and Catacomb Kids under their collective belts, UFO 50 is set in an alternate universe where the entirely fictional company UFO Soft has produced a series of titles for the imaginary FX family of 8-bit systems, which are roughly comparable to the NES in terms of graphics and sound.

All 50 of these games are playable the moment you boot up the game and take you from 1982 to 1989, neatly replicating the evolution of Famicom / NES software, with the latter examples getting progressively more complex and detailed. The earliest game, Barbuta, starts things off simple and even has loading sounds as you move between screens – just one of the myriad ways in which developer Mossmouth succeeds in achieving an entirely authentic experience, despite the fact that none of these games are truly retro.

You might be tempted to compare UFO 50 to Nintendo's WarioWare franchise based on the concept alone, but that's doing this package a massive disservice. It's not that WarioWare is bad; rather, it's that UFO 50's games are so fleshed out and deep that calling them "micro" or "mini" is a downright insult. Some of these titles contain hours of gameplay and compare very favourably to many NES classics in terms of replayability and longevity.

Our personal favourites include Seaside Drive, a side-scrolling shooter which showcases an OutRun-like vibe. You drift your car to keep your projectile power high, and you face off against both land and air-based enemies.

Then there's Pilot Quest, a futuristic action-adventure with a Goemon feel and an Animal Crossing-style town-building element; you repair your spacecraft, you need to help out local aliens find the materials they need, and there's even an exploration-based section where you hunt for resources whilst fighting off enemies.

Valbrace, one the other hand, is a first-person, Dungeon Master-style RPG which boasts challenging real-time battles and some fantastic presentation. Cyber Owls is an intense Contra-like action platformer, but with owls (obviously), while Fist Hell is a Mighty Final Fight clone in which you punch zombies. Onion Delivery is GTA meets Crazy Taxi, Kick Club fuses Bubble Bobble with Soccer Kid, and Warptank is an inventive gravity-inverting puzzle shmup. The sheer level of invention and innovation on display is simply staggering.

It's not an exaggeration to say that there are weeks – if not months – of solid and captivating gameplay on offer here; not only do the games boast impressive depth, they also come with flesh-out (and often amusing) fictional histories, and each one offers a bonus unlockable, which can be placed with a special 'Garden' section of the game.

While some of the games are predictably better than others, all of them are worth at least an hour of your time, if not significantly more. This really is like stumbling across a vintage system with 50 must-have games, all in one go – and that makes it an essential purchase, not just for retro fans, but for anyone who finds video games even remotely appealing. Simply put, UFO 50 is a masterpiece.