to run a virtualized version of Android x86 (for PC) on your Ubuntu Mate system follow these steps:
Install a virtualization program such as Virtual Box. To do that click on
System -> Administration -> Software Boutique
then search for Oracle VirtualBox then install it.
Download Android image installation file from here:
*I tried the last link which was for version 5.1 and confirm it is working fine.
I tried the live cd version but for an install you can the follow this guide:
Once done maybe you want to try Kingdom Rush and its sequels Frontiers & Origins
Enjoy it & good luck