Yes, its Evochron Mercenary!

As for aiming, by default the game will auto-aim for you. You can turn this "combat system" off with a single key press though and manually aim for a red marker indicating where the target is going to be when your shot gets there. I'm nowhere near good enough to do that however.

It's pretty awesome, watch a video, grab a demo.
http://www.starwraith.com/evochronmercenary/index.htm

Here goes. This is a prefect example of why I like low budget games.

Earth Defense Force: Insect Armageddon? I doubt it...

EDIT:
Monster Attack?

Earth Defense Force 2017

LOL. No to both of them, but your are fricken close on both guesses because they are all in the same series.

Thats the correct one right there!

I'm fine with coming close. I've been running short on ideas about what games to post anyway.

This isn't like VVVVV where I should have known.

I am a bit short myself, but OK

This one should be easy,:

Well that seems to be the Winter War from 1939-1940.

As for the game, my best guess is Hearts of Iron 2.

I thought Hearts of Iron too but the screenies, while similar, didn't seem to quite match up, still if that last guys says no 2 I'll say
Hearts of Iron 3
Why not?

It is neither.

Look at the design of the plan, and the date (upper left). We are in 1918, not 1939 :)

I found something called 'Guns of August' which looks vaugly similar - is that it?

Good try., but nope.

Do you think I should give one more hint ? (or screenshoot ?)

This video should at least help you identify the era :

http://www.youtube.com/watch?v=tntA_4IoxbE&feature=player_detailpage

http://www.youtube.com/watch?v=tntA_4IoxbE&feature=player_detailpage

[The video are not part of the game]

So that would make it the Finnish Civil War. Hmmm...

Oh... not only