Hey! This is my first for a lot of things: A horror game, a game trailer, and releasing a game in general (despite being a roblox dev for almost 3 years at this point)
So, how can I improve for next time? I know the chat shouldn’t show, but I’m not the person who recorded the video so I cant control it that much.
Here’s the trailer:
Rating: 8.0 / 10.0
It’s a good looking trailer. Direct, suspenseful, thrilling, and hands the user a hint of excitement, which attracts them to click that big, green play button in your experience’s page. However, I’d like to note down a few issues and possible improvements to add to your trailer.
These are suggestions on what to do. There’s more step-downs, but they’re already highlighted on other replies. Regardless, it’s a good trailer for your first time! Keep it up, and watch out for further errors! 
I like the music a lot and the video and the text it looks really good. I think maybe you should add some more scary bits since it’s a horror game, it looked mostly like an endless empty corridor to me. I really like the editing though
Look at the end… Maybe that is what is missing…
As someone who is skilled at editing and filming, you actually did pretty good for a first job but I have a few suggestions.
If you’re not using freecam to record, you can disable the mouse texture temporarily until you need to turn it back on.
Try adding some clips that are what the text is based around. For example, start walking slow and looking around to add effect to the trailer.
For the suspense part of the music, you can start running to add even more effect to the video!
I noticed you had the chat open in one part. If you’re filming it, keep your chat closed at all times.
If you want to maximize effect, you must actually add characters chasing you a lot of the time but like @datBlueh4t said, you can add some camera shaking effects.
Also, I noticed that you didn’t do so well with the freecam shots, try using a smooth camera plugin like this one made by sleitnick: https://create.roblox.com/marketplace/asset/883602387/Smooth-Cam (I don’t condone any actions if you install this.)
As a video editor, there are a few things I wanna point out…
First off, the cutscenes from your game should be based on different player’s perspective of gameplay, let’s say if you have about 6 people to play your horror game, and got each of their pov’s trying the game out, you can use differently on each cutscene you wanna place and use them on…
Second, the font of the text used in your trailer, if you want to give the horror vibe and feeling, you gotta at least use a font that gives more of a “haunting” type rather than a “default” text type, if I were you, I would change the font to a Faber-Castell type of font, which gives, an old castle vibe, indeed, but also gives a general horror feeling to it as well.
Third, the cuts between the text and the gameplay in the trailer, it is best to sync your audio with the cuts and as well as when the beat drops. Because, here’s the thing that sells off, when your video switches between text and the gameplay videos, they should change between each other in a precise timing, except for the end of the trailer, I’m a fan of it. You did synced up the Nov 5 2022 date quite almost well as with the title of your horror game.
Fourth, this is not too much of an explanation but, basically, at the end of your gameplay video, when at the last, the monster of the game is being shown, I would rather show that its jumpscaring, as if whether its roaring into the camera/player pov and etc…
But nonetheless, I like the motive of the trailer as if to where its intention is, good job!! You’ll get better 
The main issues I could see are that you recorded it in first person instead of using free cam and also that at some points the chat window pops up. Overall great job!
It looks pretty good! Very good work!
The trailer looks pretty good! I would just recommend not to include the mouse or game chat. And maybe use freecam or a scripted cutscene camrera. Still good though!
It’s not bad for your first time, but I would work on giving it more action. Blend scenes together using sound and visual effects. I also recommend that you avoid repeating similar scenes or frames. Lastly, there should be a clear buildup, climax, and resolution in the trailer.
An easy way to resolve repeating scenes is to include both cinematics and gameplay, not just gameplay.
Here are some example trailers from my own work that you can use for reference:
super cool, I would hide the cursor though
Looks neat, but try to add some freecam footage rather than just POV. Additionally, maybe don’t keep going back to that same scene too many times. Trailers have to catch peoples attention!