Horus the Horus Heresy: Legions has a number of great features that make this a great choice for the Android mobile gaming audience. From the first level you will be playing against the AI and the level is designed to be very challenging. You can take on missions and fight battles in order to earn XP and rank up your character. This game has the ability to transfer to iPhone from Android and you get to use the same controls and interface you would if you were using an iPhone. It also has a multiplayer mode where up to four people can play each level and you can see who is the strongest in the game.
This game is packed full of features including, an online multiplayer mode, mission modes, leaderboards and achievements. You can also download other games from the Android store, just go to the Google Play store, the app stores or the Amazon marketplace and find the game that appeals to you. There are a lot of good free applications out there but I'm not sure if these are worth it unless you need a specific feature or if you just want to try something new. The Horus Heresy: Legions software allows you to download games for free but it has so many features that you really don't need to spend money on it. If you are just looking for a game and don't care about the options then the Android game will be fine for you.
If you decide to download the Android game, I recommend downloading it for a limited period of time so you can find out whether you like it or not before buying it. You can always download other games in the future, especially if you want to play them on a different platform. If you are worried about downloading viruses or spyware, just install it in a location that you will never lose access to it. I would recommend playing this game through an internet browser because it provides you with a much better experience and doesn't require any downloads of files or anything else that might put your computer at risk.