I think you could do something with the length of your videos. The average viewer is certainly not going to watch a 40-45 minute video ( there are exceptions, but they are rare). I'd say cutting it down to 15-25 minutes would be good enough!

Don't talk during cutscenes
Don't try to be funny ALL the time
Do a little research so you can drop some info on the game/development/actors occasionally
Play the game as you would play the game and don't rush for fear of losing views
Use your own voice and forget about any other Youtuber. Be yourself.
Don't constantly ask for subscriptions. Do it now and then.
If you get new subscriptions, thank people for it (not by name)
Make sure you update regularly and try to stick to a routine.
Have a good quality capture card (1080p)
Have a good quality mic.
Don't just stop the episode in the middle of something. Try to make the cut off point a cliffhanger.
Don't make your intro and outro ridiculously long
Don't talk through cutscenes.

I watch a lot of let's plays and any site that ticks these boxes is on by subscription list.

You should get really drunk and stoned while you try and play really hard games. Perhaps throw a few controllers around. Maybe show us interesting ways to take a piss while playing that involve not getting up off the couch. Do a couple racist comments that are relevant to whatever game your are playing.

can you watch my video #9 and lemme know what you think?
Also, I agree with all those points. Especially the not talking through cutscenes part. That's really annoying.
Thanks for the tips;

-Have something interesting to say and put some energy into your expression.
-Don't talk during cutscenes.
-Don't use terminology without defining.
-Don't assume people know everything about the game in the earlier stages. Explain stuff for the first few videos, and then assume that maybe a few hours in, people have started to understand what's going on.
-Have an interesting voice.

I would try to cut down on talking, just a tad, just a tad. If you have slight lulls then it makes what you say more impactful. When I say a tad I MEAN a tad ... just a beat or two. Get a better mic. It sounded OK but not as warm as it could be and a warm voice is good for Youtubers. Listen to CobraTV to see what I mean. You have a good voice for Youtubing so make the most of it. 1080p!

Is this constructive criticism or just general advice?

Just wondering in case you saw some of these errors and made notes as a result.

There's only one rule. Scream a lot and it = all the Internet monnies.

Stupid average viewer -__-

I love 45min+ vids. Anything thats 15mins seems pointless.

I don't mind longer videos either, but that's something he should do if he wants his potential viewers to fully watch the videos!