I found this intriguing. I think it is a good improvement, your games are getting better as you go.
The art could use work but it also has a quirky quality to it. Needs some fixes; weapons should probably disappear after I die, grenade is kind of hard to use, etc. The game could use some more advanced mechanics. But I assume you know all this.
I would really like to see some story. Even if it is just a tiny blurb at the beginning of the game. Give me a reason to care about the player and want to finish the game. I am usually more forgiving of a game if it has a story that makes me care.
I enjoyed it. The last room upgrade made me laugh.
I would suggest maybe adding more upgrades to the room. It would make me want to play longer to finish up the income upgrades. Or maybe add some other reason I would want to keep playing. Maybe different types of ways to upgrade the income.