Great demo! Enjoyed the base mechanics and the overall direction of the game, even beat it pistol only! As a big fan of Receiver (2013) I appreciate a shooter that lets me fumble with realistic controls. But I think the game could benefit from some more player choices and (at least optional) increase in difficulty.
1. Running should impose stamina drain, or have a separate "heat rate" effect where your aim has increased wobble/shake/vision tunnelling if you aim immediately after running for 2 or more seconds.
2. I never had issues with ammo as there was so much of it (maybe reduce?), but I did have a problem holding onto half empty magazines I didn't want anymore. Having the option to throw away magazines from the tab "inventory" menu would be great.
3. It would be great to be able to aim down sights after getting the scope attachments.
4.Speaking of attachments, It didn't feel like the attachments had much of an effect on improving the rifle? You could have the base handling of the weapons be much, much worse without them and Maybe add a tool tip when hovering over the attachments to indicate what benefit it gives in order to make it clearer.
5. Things that might flesh out the experience: Suppressor/Attachments for pistols, Grenades with controls for pulling the pin etc, weapons in similar platforms to AR15/ M1911 that could share the same basic animations to cut down on development work, adrenaline or morphine ampoules that distort vision but give 25% healing, claymores or trip-mines.
6. Finally, the bots are a good difficulty for beginners but harder versions/ types should be made, maybe in different colours to denote danger level. Bots without lights/laser sights when aiming so they are harder to keep track of. Bots that push further when searching for the player. Taller bots with heavy machine guns. Smaller bots with sniper rifles and so on.
Anyway that's just my two cents, loved the game, wishing you the best with the project!