Great concept and tone, and I love how this condenses something like Monster of the Week into something even more digestible and on-boardable, with the simplified archetypes and GM tables. The Advantages and Disadvantages are really clean and fun, and the GM's side has just enough depth without being overbearing for even a one-shot, although I could actually see a group like mine playing this for a couple sessions! Love it!

Looking through submissions, I can see that we love using the 2d6 XD
But not about it, what I like the most in this submission is the possibility of a Scooby-Doo session  with real aliens, although we don't need to know it.
Plus, quite simple mechanics and lots of alien races to defeat.
Just play and have fun.

Taking it in order

2 stat system makes sense for a game this short.  Sports and Smarts are good names for them too.  Alliterative and fit the genre.  Should probably put a bit about what they're for near this though I had to skim the rest of the doc to figure it out before continuing.

Architypes are perfect, and throwing Dog in there is icing on the cake.  The advantages and disadvantages are a little confusing.  Some of them have clear narrative/mechanical implications like a nerd and their glasses, rich kids having money, etc., but others like a jock being good at sports overlap with the stats you already outlined.  If a jock is good at sports they should have a good sports score, not an ability that says they are.  You could make a literal +1 bonus to that score or something, but I think the narrative abilities you have for some of them are more interesting.  Maybe the jock can call in some guys from the football team for backup, but is quietly hated by all the nerds in the area.  

The list of aliens are good, they all feel unique and would lead to very different games.  I think ability/weakness might be a clearer name than advantage/disadvantage.  Could use it for the architypes too.  Some of the language like "Toxoplasma gondii" could be simplified.  

Plot options are also good.

2d6 roll under feels right for this.  I'm generally not a huge fan of roll systems with no mechanical way of adjusting difficulty, but I think this game is loose and lighthearted enough that it doesn't matter.  

Crits on your number means that mathematically someone with a 6 or 7 sports is more likely to crit on a sports check than someone with 9 sports.  I don't think it's a huge deal, but you could try doing a 
"if you roll 4 under your score" system instead.  You'd be about as likely to crit with a 6 or 7 stat, but would be more likely with higher stats than lower stats.

Cowering on a double 1 and overexerting on a double 6 feels backward for a roll under system.  

Adding a d6 and choosing the best 2 is a very nice way to handle helping.  

Alien Influence is a weird one.  I like the abilities you've given the aliens for it, but it's never in the parties interest to take that 6th point.  It's both mechanically brutal and means that player either needs to play villain or sit out.  I think you could solve this by making the threat a little more open ended.  The party adds to the pool collectively and at 6 alien influence something "really bad" happens.  This might mean the Uvuuls mind control an important NPC, the Zetan reanimate a whole graveyard, or something else the GM thinks would be good on the fly.

GM advice is solid.  Failing forward and a reminder to push the story in interesting directions is always good to include.

Plot twist table is great, love everything about it.

On the whole I think the biggest selling point to all this is the atmosphere.  The game fits the genre really well, and the genre is fun as hell.

I really like the idea of playing as particular archetypes / trope-y characters, and each gives a lot of info very concisely! I also like that there's a lot here for running the game. Good stuff!

This is really cool! I like the aesthetic and the alien/plot generators look great. I also like the twist mechanic. Overall this seems like a fun, narrative-style game.