I could reach Hour 7! Nice interesting game and i love these types of tower defense type strategy games where the focus is on resource management. I played for 3-4 runs and tried a few different strategies and heres a few points that i have:
1. The difficulty of the game is a bit high i think (was atleast for me). The initial few rounds are easy, but once the larger monsters start coming from the left, i kept running out of ammo. I think the amount of money earned for every kill can be increased or the cost of ammo or heal can be reduced.
2. Getting the 2nd turret seems almost impossible since you need to keep getting ammo to refill, so i kept fortifying the same room and using the same room to be attacked. once in between, i fortified one room and chose the other to be attacked, just so that i could save on ammo and earn points for clearing the level but that didnt work out in the end! So i just feel that there are not many viable strategies for the player to use, and sticking to one room might be the default one.
That being said, the gameplay is really fun. You have managed to add a lot of juice to all of the elements including the menu, option selection, text etc which is great. The shooting itself and killing zombies is really fun and the faster zombies add some nice variation. The art is also really good and the music and sound effects match the gameplay well. I think if the difficulty were reduced by reducing costs it would balance the game nicely and would make it even more interesting! Overall well done though, i had a really fun time in the few times i played :)