Years ago there was a tabletop game called the space hulk. It was about mighty space warriors battling the sinister genestealers in the corridors of the abandoned old spaceships. It was really cool game. But in required you to invest a bit of money into the figures, paint them and find a partners to play with. But it was worth the effort.
Templar Assault is a worthy successor for this awesome game. You assume the control of the team of the mighty warriors from the Templar Assault order and lead them to fight the evil xenos. Each of your warriors have a limited number of action points and health points which combined with large numbers of enemies quite often make your life really hard. You have to plan carefully your next steps or risk losing the soldiers. Also forget about standard run and gun strategy - you have to make sure that your people cover each other and that they won't have any enemy behind their back because that would certainly mean death for them.
Each successful mission means some experience points earner by your brave warriors. You can spend them to make them stronger, more agaile or better at handling the weapons. Additionally you can buy some additional equipment like extra ammo clips or gear that adds to range or tactical skills. And of course guns. Lots of guns.
Graphic is quite minimalistic but it serves it purpose. It's clear and don't disturb you with tons of fancy effects which makes sense because game is tactically oriented. It's not a modern hack and slash where you have to tap your way through the hordes of enemies. Here you have to think and plan. Music and sounds effects are also fine. Nothing fancy but it's perfectly fine.
Overall - it's a good game and I would recommend to go grab your copy. You can try the free version first and then upgrade to the elite if you will like it.