Overall, very simple but engaging! I am a big fan of browser games that are top-down shooters with this kind of control scheme, I think that is partly because I am a big fan of shooter games in general. Your game has an easy to understand concept, but I have some things that I think would really help without changing too much.
1) Add a crosshair; adding a small sprite that is set to the position of the mouse cursor will make it easier for the player to connect in their mind that the mouse position is where the player's bullets will go to.
2) Add feedback when the player takes damage; when the player takes damage, their should be a sound effect and a visual indicator (like the player color changes to red for half a second or so) to indicate better to the player. Although the text box with lives in the top is accurate, I found it hard to check due to the next thing I'm going to address.
3) Fix the text overlapping and canvas size; I noticed your game is cut off slightly by Itch.io. Although your games canvas may be the same size as the itch.io window size/canvas size, I noticed itch.io adds some padding on the left and top edges of the game which pushes it just slightly out of view. As far as the text goes, I would try shrinking and rearranging where your text elements are on the screen, as they were hard to read, especially when having the dual-wielded pistols equipped.
4) Add more feedback to the bomb; The bomb's feedback when exploding is great, but before it explodes, it is very static and can even be hard to tell what it is. I think adding an animation to the bomb like making it fade back and forth between it's regular color set and a red color would invoke a sense of urgency to the player that is lacking. Adding a hissing noise (or some kind of noise that would give the sense of a fuse being lit) would also greatly add to the feedback to the player that it's very dangerous.
I know I wrote a lot here, but it's largely because I like to be very descriptive. Your game is very good and fun to play! I really didn't see any bugs in your game besides the text overlapping, and the gameplay itself feels good and is very engaging. The art is also very well done in telling the player what each object is. You did a very good job here!