Honestly, this isn't very good.
Yeah, it's good by Newgrounds standards (which aren't very high), but if you want to put it on Steam as a commercial game, you gotta try harder.
I will start that I like the retro low-poly graphical style. However, that is pretty much the only thing to commend here.
Music is... alright. I didn't really notice it, but it's not OFFENSIVE. Similarly, while voice acting is bad, it fits the style and atmosphere of the game.
Humour isn't good, and for a matter of fact - it's almost nonexistent. If you want to see how to make a funny spy movie parody as a game, I recommend playing NOLF games, or Jazzpunk - they did the same concept ten thousand times better. Hell, even Austin Powers stuff was funnier than this. None of the jokes (if we can call them that?) stick the landing, there is very little comedic timing. One actual joke - the parachute not opening - I actually missed because I pressed left-click several times trying to see what happens, and dialogue has overriden itself, ruining the joke.
Speaking of which, writing seems... unfinished. "We're still repairing your last escapade"? What happened to that poor escapade? :P
Gunplay feels very bad. The whole thing with bullets being physical projectile that come out of right side of the screen is ridiculous - it feels extremely bad, why not make it more like modern shooter? While there is some auto-aim, it's often glitchy, and e.g. it made it impossible to hit dudes on the beach level if they were too far away. I understand that you want to imitate N64 Goldeneye, but that game was releasing in mid-90s on a console with one analog stick, there is NO REASON to try to imitate its controls now. We're playing this on a PC, there's no need for auto-aim. Everyone knows how to aim at any point at a screen, pretty much everyone in the audience played an FPS once.
I mean, you could also make the game more complex! If enemies didn't die in one hit, maybe it'd be worth to add headshots, or something like that! There's a ton of ways to make shooting fun, and not a chore!
Guns feels extremely weak - they have no punch, they are inaccurate, sounds and visual effects are lame. Similarly, enemy death sounds are pathetic. As a result, mowing down enemies isn't even fun. Maybe look up some articles or videos on 'game feel' to spice it up a bit.
I've seen two weapons - the SMG and pistol - and SMG is only SLIGHTLY better than the pistol, considering that pistol shoots as fast as you can press mouse. Why not take a page from Doom's book and add a cool shotgun, or something like that?
Here's some people smarter than me talking about what I mean:
In addition, enemies aren't very challenging. There is NO REASON for melee enemies to die in one hit - it makes it almost impossible to die from them, especially since your default pistol has unlimited ammo and no need for reloading. For an experienced FPS player, combat will be pathetically easy - I recommend adding different difficulty levels, with current difficulty being "easy".
The only time I died from this game is from running out of time. Speaking of...
Level design were alright, if mediocre most of the time... except for when it's not clear which door was unlocked by the "7 ring" (speaking of which, what is the point of it outside of taking me out of the game? Couldn't you have just made a switch like in Doom?). At one point at a beach I just ran out of time because I had no idea where I was supposed to go next (door behind me was closed). I could've retried, except... game isn't fun. It's pretty boring, and I have no desire to keep playing it. If this was on Steam, this would be the point where I'd refund the game, and boot up Doom or Duke3D again.
Pacing is all over the place, too. The first thing you want to do is for player to do something interesting and exciting, NOT walk around in a lame base with no clear sense of objectives, what to do next, and possibility of accidentally exiting to main menu. Speaking of which - why is there no objectives? You're clearly riffing on N64 Goldeneye, but it and Perfect Dark DID have unique objectives in every level, and weren't just corridors filled with enemies.
In addition to that, level designs lack anything interesting or memorable about them. There's no gimmick, no setpieces, no interesting mechanics - nothing interesting or original. It's just pointless corridors filled with enemies. Nothing to remember the levels I played by.
Why should I play this game over any OTHER fps on the market? Because if you can't answer that question, maybe you should seriously rework how your game works.
Riding on nostalgia alone won't take you far.