Revenge of the Titans has entered open beta, and is available to download from the Puppy Games site.

It's an RTS-cum-Tower Defence game, with an alien invasion setting. The Titans are attacking Earth, and your job is to place a variety of guns and structures to fend them off.

Along with the beta, the game is now also available for pre-order for half price, making it £10.75 / $14. While it looks fantastic, the final asking price does worry me a little - it will cost $27.72 / £19 eventually, and as we've learnt in the past, a number of indie gamers aren't happy to part with more than $15, let alone double that.

Still, if you check out the beta and enjoy it, the pre-order price is perfectly reasonable. Note that the beta release contains two of the fives levels that'll come with the final version.