The success of Flappy Bird demonstrated what little difference graphics can really make when you're going for the "addictive and free" route. In a show of graphics being secondary to gameplay, we've found four free retro-inspired games will keep you hooked to your iPhone.

The use of 8-bit graphics doesn't necessarily mean that developers have it easy and many work even harder to recreate an authentic retro gaming experience. These games bring the best of retro gameplay – challenging difficulty and classic chiptune music – to your smartphone.

Only One

There's an island above the clouds. A white sword is on the island. The player teleports to this island, picks up the sword and proclaims, "I will become... the Only One."

Wait, why is he there? How did the sword appear? Why does he want to be the Only One? You might find out if you can survive Only One's 70 levels. The chances are that you'll be too busy trying to fend off wave after wave of enemies to ask those questions in the first place. An easy way to kill enemies is to push them off the edge, but don't forget that they can do the same to you.

Only One uses a floating D-pad for character movement and four buttons for attack and special powers. There are checkpoints every 10 levels, right after you beat the boss. If you die before beating a boss, you'll have to start from the previous check-point (which could be nine levels prior). Although the game doesn't have advertisements, in-app purchases let you buy power-ups to speed up your progress.

The virtual D-pad left me with a sore thumb after around a couple of hours, but the game is too enjoyable for me to complain (or put down).

Disco Zoo

NimbleBit LLC, the makers of Tiny Tower, which featured in our best iPhone games list, have made another massively addictive 8-bit game – Disco Zoo. This time around, the game makes you the owner of a brand new zoo in town. Don the owner's hat and prepare to “rescue” animals from the farm, savannah and beyond to populate your zoo.

The more animals you have, the faster you earn coins. So then why is the game called Disco Zoo? Because you can turn your zoo into a disco for a short duration to double earnings. This costs you Discobux, which are harder to obtain than coins but in-app purchases let you buy Discobux if you want to.

Disco Zoo has seven different habitats from which you can collect your animals. Every rescue mission costs around 10 coins more than the previous attempt. This involves tapping on tiles, which may or may not have an animal underneath. You rescue an animal only when you find three or four tiles of that species. This can be frustrating.

The game also keeps sending you notifications when animals “fall asleep”. You'll have to tap once to wake them up so that you keep earning. If you ignore these two annoyances, or you especially enjoyed Pixel People, Disco Zoo is fun to play.

McPixel Lite

It's your turn to save the day! McPixel Lite is a fun old-school point-and-click game. You have 20 seconds in each level to prevent an explosion. There are no hints regarding which object will help you survive, so you will have to rely on trial-and-error. This is going to cause a lot of frustration because some of the objects you need to find are very well-hidden.

On the plus side, trying again and again isn't so annoying thanks to decent music and the many funny ways in which McPixel (your character) can die. The game is fun, but it could do with a pause or menu button. Once you start playing a level, you can't return to the menu until you finish a set of six levels.

McPixel Lite is free, but the number of levels is limited. If you want to play 50 more levels, you can buy McPixel for $2.99. The game isn't just about preventing explosions though, and there are plenty of objects to find before you can 100% complete all of the levels!

Buy: McPixel ($2.99, has additional levels)

Impossible Pixel

Have you been looking for a good 8-bit platformer? Try Impossible Pixel. You'll need to navigate a treacherous obstacle course to reach the exit in each level, much like Super Meat Boy. In fact, some of Impossible Pixel's obstacles look just like those in Super Meat Boy.

The faster you reach the exit in Impossible Pixel, the higher your chances of scoring three stars. This game also has a hard-to-reach coin in each level and both of these elements ensure that you can play through the game more than once. There is plenty of game here to keep you occupied for a long time.

Impossible Pixel has the occasional annoying pop-up advertisement, which I have clicked accidentally a few times. There's no way to pay to disable it, so you might as well get used to it. If you don't mind that, this game is sure to keep you hooked.

Don't Mind Paying?

Free games are always welcome, but the App Store has some great retro-style games for a few dollars each. If you're looking for a fun adventure game with witty dialogue, Superbrothers: Sword and Sworcery is an amazing choice for $4.99.

Apart from that, The Other Brothers ($1.99) [No longer available] and Knights of Pen and Paper ($2.99) are two of the best retro games on iOS. The former is a tough adventure game, while the latter is a great RPG. If you have already played these games, check out Tim's list of iOS games to look forward to this year.

Did you like these retro games? Have we missed any of your favourites? Speak up in the comments section below.