The tenth iteration of Undead Invasion is now out; the game now includes 22 levels, 3 heroes (with a wide array of different abilities and units) and a fair assortment of fiendish enemies.
The game uses graphics and animations created by the talented Reiner Prokein, who very kindly makes his work freely available.
You can now play my Android game Dropwords on the web! Give it a try!
I ported the game to run on the web using the excellent Unity3D game development tool; theoretically, with a bit more work, I should be able to make an iOS version too!