This is a decent start. The basic mechanics work well.

I like that there are protected areas, especially at the start before you collect your first weapon. It would be nice it the starting point was looking at the entry to that first building to help guide where to go, rather than looking around and suddenly being attacked with no way to defend yourself. 

The enemies were pretty easy to deal with, as long as you had a weapon and ammo. The turrets that shoot back fell like they should be tougher than the spiders, though with them shooting at you I appreciate that they are not harder to destroy.

After I got the second weapon (Gatling) I did not know how to change weapons. It was more useful, and I finished the level before running out of ammo, so it wasn't too bad.

I did not manage to find any weapons on the second world. I found a town where I could walk through buildings, lots of ammo, and lots of enemies. Just no weapons.

Twice the game locked up on me. It killed WebGL and refreshing the page gave me an error about not having WebGL the first  time. I had to restart my browser to be able to play again. The second time I was able to replay after refreshing the page, but had also taken time to write this comment before trying, so maybe the delay helped. The first time was in world 1 as I was trying to figure things out and was pressing G to get to the menu. The second time was after I made it to world 2 and had run around a bunch. Based on the console messages I think it is memory related, but I'm not certain. I was playing fullscreen on the web when both crashes happened, so could not see the system stats. It took a while after locking up before it closed.

It is good that you have the controls on the web page, but adding a short in-game tutorial, or even signs with text giving instructions, such as the basic controls, would be nice. The second area could also use a bit more guidance on where to find your first weapon.

Overall it felt like a good base. I stopped playing due to the crashing, and would have played a bit more and tried to find the weapon otherwise.

I've not had a chance to play the game yet, beyond starting it. We will play later and give a review of gameplay then. Here are some thoughts based on first impressions of your game page.

There are 2 things that very strongly stood out as soon as I opened your game page. The first was the number of jams you submitted to. Over time submitting to many jams can happen if you submit to continuation jams like this one, but a fairly new submission with that many jams stands out. As soon as I saw the number of jams I started looking at the names of them. It was very clear that only some were continuation jams, and that your game was unlikely to be able to qualify for for all of the jams. Many jams are exclusive, meaning you must create your game for that jam and cannot submit to any others during the jam. I looked through your submissions to many of the jams and see that you have been disqualified from several of them already. Being seen as someone who spams your game to jams it does not qualify for will build a bad reputation. You may get banned from being able to take part in those jams in the future, even if you were planning to follow the rules for a future submission. Before submitting to any jam be sure to read all the rules and make sure your game qualifies.

I have not seen anything so far that would disqualify your game from this jam. I just wanted to point out that it looks bad when you spam many jams you don't qualify for, and plenty of people will skip your game as soon as they see that. Were this not our jam, we would likely have move on from your game as soon as we saw the submissions to jams that disqualified you. My first thought when I saw the list was questioning if we were going to need to remove your submission. I'm happy to see that you are already active in the jam leaving feedback, and that you do have an actual game submitted.

The other thing that stood out was the color choice. The yellow on red can be hard to read. If you want to keep yellow and red, I would suggest adding a bit more contrast. Make the red a bit darker. The yellow might be able to be a bit lighter as well, but I think the darker background would be the bigger help for readability.  It will also help with the links, such as to your devlog, which are a pinkish color and really hard to see against the red background.

Speaking of devlogs, you don't need to fill out all the fields to submit to this jam. Only the first is required. The rest are optional. You can click on the "Edit this submission" button and remove your "devlog not ready" text until you have one ready to put there.