Pay-per-stage in new freemium version of Square Enix's Crystal Defenders

Square Enix has released another version of its challenging tower defence title Crystal Defenders. This time around, though, it's in freemium form.

In this new incarnation of the fantasy franchise - entitled Crystal Defenders Plus - you can try out the first 20 waves of the game's training stage, Bisga Greenlands.

As soon as you feel ready, you can buy the remaining stages from the original Crystal Defenders game via IAPs. You can pick them up individually (£1.49 / $1.99 each for stages W1, W2, and W3), or you can buy all three stages as a bundle for £2.99 / £4.99.

If you've never played Crystal Defenders before, pay attention. Now. In truth, it's a pretty standard interpretation of the tower defence formula, so it contains all of the TD genre tropes and conventions.

At the beginning of each level, waves of brightly coloured monsters march onto the screen along a set path. It's up to you to set up your 'towers' (soldiers, archers, and mages in this case) and try to halt the beastly swarm in its tracks.

For the time being, Crystal Defenders Plus will only feature the levels from the premium version. However, Square Enix is promising to release all-new level packs to extend the game's lifespan.

It should also be noted that the prices for the Crystal Defenders Plus stages listed above are only applicable until February 26th. After that, stages will cost £1.99 / $2.99 apiece, or £5.49 / $7.99 for all three.

Finally, Android users can now try out the entire first stage of the game, thanks to the arrival of Crystal Defenders Lite [download] on Google Play.