I think that you just say about the refreshed one(from 2020) not the oldest one(from 2003), I personaly play all games with 'SHOOTER' in title from 'SigmaTeam' and this "Alien Shoter 2 The Legends"(from 2020) has features from all games of series 'alien...' and 'zombie...' so I like it and in my opinion is the best of them. Maybe you just say about the older one "Alien Shooter 2: Reloaded"(from 2009) or "Alien Shooter 2 Conscription"(from 2012), but anyway if we talk about oldest and first ones then I think the "Zombie Shooter"(from 2007) is the most intresting.
It's here on igg too but propably better get it from other site.
https://youtu.be/aJaG2_W4XVs