The tower defence genre has quietened down a little over recent months and years, but for a while there you couldn't browse through any of the “top games” lists on the various app stores without running into one.

Sentinel 4: Dark Star is the long-awaited sequel to much-loved tower defence game Sentinel 3: Homeworld, which came out way back in 2010.

And even though the build I went hands-on with for this preview video was early, it's shaping up like it's definitely going to please the hardcore fans of the genre.