If you're still not sure, why not read our review of the full version of Halo: Spartan Assault:
After many months, if not years, of waiting, Microsoft have delivered on the implicit promise in having the gaming section of Windows Phone branded Xbox. We now know the answer to the question 'will Halo come to Windows Phone?', and it's time to ask a bigger question. Is it any good?
The short answer is yes, it's good. It's bloody good. But there is room for improvement. The presentation, top down look, and slight 3D graphical look are all fine. The level design, small but perfect, works as well. I have a tiny issue with the control system, but it is easily played around. In that sense Halo works with no major compromises damaging the game.
Read the rest of the review here.
Windows Phone Store description:
Halo: Spartan Assault Lite launches you straight onto the battlefield during the opening battle of the full Halo: Spartan Assault campaign and provides an exciting introduction to the gameplay and story of the full version of Halo: Spartan Assault.
This free trial includes the first of 30 missions available in the full version of Halo: Spartan Assault, where you’ll take command of classic Halo weapons to fight classic Halo enemies but all from a brand new, touch-based perspective.
It’s time to start the assault, Spartan!
Halo: SA Lite is a free download from the Windows Phone Store.