An intriguing action-adventure game that can be played online and is entirely free to do so is called Dodge Agent.
You take on the role of a covert operative tasked with infiltrating the opposing stronghold, which is a fortified bunker. Your mission is to get past the security system while avoiding the incredibly sneaky and threatening guards.
You can acquire weaponry of a higher quality to use against them, and while you will face a number of challenges along the way, it is imperative that you remember to avoid the hostile guards lest you be exterminated by them.
This is an action-adventure video game with a frenetic pace that puts the player's reflexes and aiming skills to the test. Are you able to successfully fulfill your task despite facing a number of difficult challenges? I hope you had a good time!