Hi,
I have played trough a bit of Xenonauts and noticed a few things that really bothered me.
Line of Sight:
Enemy and Soldier's LoS is impossible to see. This is VERY frustrating and coupled with some odd decision to prevent the player from moving in contact with some objects like the bush makes this a tactical nightmare for all the wrong reasons.
X-Com has similar problems and was heavily criticized for it. It would be a good idea to learn from them. Your actions should be as clear as possible otherwise the higher the difficulty of the game the more frustration there issue will create.
The LoS should not reset every time I end my turn. I am rather confident that my troops don't have conversion disorder.
http://en.wikipedia.org/wiki/Conversion_disorder
Some tactical situations have my men shooting from a corner, however, instead of leaning, they shoot right at the corner itself. There is no reason, what so ever, in any universe, movie, or fantasy where shooting at your cover, 30cm in front of you has ever given positive results.
Soldiers:
There is no distinction of any kind among the sprites of my soldiers. They all look like the same copy of the same character with the same weapon. It would be wise to have a variation of some kind, or at least show the names above their head.
My men, can't hit an alien the size of a refrigerator standing still in open terrain 20m away from them and are blind to anything past 30m. I am no expert but that's immersion breaking to me.
Lose the blue uniforms, they have no advantage.
Sounds:
Footsteps are way too loud and having the alien phase transition to a loading screen is so immersion breaking that any ambiance the game created so far goes out of the window. TAKE OUT THE ALIEN PHASE SCREEN !
Tutorials:
Your game needs them.
Here is a good representation of how your soldiers feel in battle:
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