Let's not beat around the bush - Outernauts takes a huge leaf out of the Pokemon book, sneaks it into the photocopying room at work, and then returns it and hopes nobody noticed.

There are whole sections of this free-to-play browser game that copy the Pokemon series move-for-move, giving it a slightly cheeky undertone throughout.

Naut to sixty in a few hours

You play as a space cadet in a world full of strange creatures doing battle with each other. You've been tasked with removing the dark and sinister corporation that's threatening to tear up the world.

The Pokemon inspiration shines through from the start. Each creature has a type, and some types are more or less effective against others. When you walk into wild creatures or trainers in the world, the game becomes a turn-based battler in which you use moves which cost 'stamina'.

From the flashing screen as a battle fades in to the fact that you can hold a party of six creatures to the way in which each creature can evolve twice through levelling, the degree to which this is essentially Pokemon in a browser is breathtaking.

As you push on through the game it becomes clear that Outernauts makes the best of its inspiration, taking the gameplay of Pokemon and enhancing it with social gaming elements.

It also owes its success to the excellent integration of missions and customisation. Missions filter down the left-hand side, like in every single social game ever, but these do a wonderful job of forcing you to explore different worlds and use different creatures in battle.

It's notable just how well-presented the whole experience is, too, from the humourous dialogue to the gorgeous, comic-style visuals. There are graphical glitches here and there, but for the most part it all goes off without a hitch, as you'd expect from the studio that produced Ratchet and Clank .

Down and Out?

Of course, this being a free-to-play game, you're frequently encouraged to fork out for in-app purchases. It's a little jarring at first, but it soon becomes apparent that you don't really need to pay anything at all to have a good time.

Battling against friends and strangers online costs a little more energy than regular moves, but it's far more worthwhile as your battle ranking raises and you shoot up the online leaderboards.

The customisation, for the first couple of days at least, won't set you back any cash either. You can collect materials in-game and use them to craft new items, battle advantages, fuel for your ship, and creature upgrades, while visiting friends' planets gives you the opportunity to grab some loot while helping them out too.

After several hours of play, you do admittedly hit a carefully disguised paywall, in that you'll be waiting around a lot more to get things done thanks to the sheer number of items that each mission wants you to collect.

You'll hit a similar invisible paywall for customisation. Player costumes, for example, pretty much all cost real cash, and - annoyingly - these costumes aren't just for show, actually giving you an advantage over other players.

The game also forces you to sign friends up later into the game, or pay real money to skip, which is a particularly obnoxious example of freemium design.

But it's a testament to Outernauts's addictive design that as soon as we've finished this review we'll be heading back in to play some more. And, let's be honest - until Nintendo decides to break the habit of a lifetime and release a Pokemon game for your browser, this will do very nicely.