Angry Birds Transformers plays very well, there's no denying that. When the game is letting you access its content, you'll have a great time with it - transforming, rolling out, and blasting baddies with impunity.

But every once in a while the game's free to play model gets in the way of the fun. "Hey! You! Can you go away and do something else for a bit instead of play this cool game?" it says in not so many words.

It's still good, still worth playing, but it does need a few tweaks to make it the brilliant game it could so easily be.

Starting out Optimus-tic

The core shooting of Angry Birds Transformers is always explosive, usually thoughtful, and occasionally chaotic.

You run automatically along a path and are presented with targets to take out. These come in the form of the green pigs, who are firing lasers while perched atop teetering structures of wood, glass, stone, and so on.

Much like earlier Angry Birds games, your task isn't necessarily to shoot the pigs directly, but to shoot surrounding weak points that will cause their position to crumble, popping them in the process.

The aiming can be a little inaccurate. Sometimes I would go to tap one beam, and the game would assume I meant the one slightly above it.

But that one minor hitch is my single issue with the moment-to-moment action, as it's otherwise fast-paced fun with some Transformers gimmicks thrown in for good measure.

Hitting one virtual button on the screen transforms your robot bird into their vehicle mode, allowing you to speed past tumbling towers that would otherwise squish you. Others let you throw up a shield or activate an all-encompassing death explosion to even the odds.

Yet another button calls in a pal to help you on your journey. This is a a good egg you pick from your list of friends (or strangers) before you enter a stage.

Thwack the button and they land with a thump, destroying everything around them, and then trotting alongside next to you while shooting porcine chumps.

Duh-duh-duh-duh-duuuuuuh

Each rendition of each character is superb too, and there's a feeling of humour and silliness throughout. Transformer selfies, doing The Robot, moustache twiddling, and more.

The Transformers and Angry Birds licences are used brilliantly, frivolously, and often to make fun of the respective franchises in a good natured way.

However, just as you're laughing along at Heatwave's social awkwardness, or marvelling at Galvatron's Metallikato moves, Angry Birds Transformers puts a halt to the fun.

Wait timers and currency are everywhere, and they make for an overarching structure that is the antithesis of the frothy and fast play.

You wait when you upgrade your robot, you hang about until you can grind the level again for coins, you spend huge sums of currency unlocking new regions with tiny numbers of new stages in them.

If you were at a theme park, the gameplay of Angry Birds Transformers would be your mate egging you both to go on the bloody great rollercoaster, and then barfing everywhere and laughing at the barf he just barfed.

The monetisation is the guy you felt bad for because he hasn't got many friends, so you invited him on the trip but he's constantly checking his watch because he has to get home and do some taxes.

And no he won't have a picture taken from when he went on the teacups with you because they're just a waste of money anyway and the burger and fries were a rip off too.

Angry Birds Transformers then. When you're transforming just in the nick of time to avoid a falling stone stack, and the game slows to a close up of you winking at the camera it's great.

But when you're grinding for currency, and being turned away from the content you want to access, it's a real drag.