Fix what? If the game doesn't run at all, then it's your browser's fault, so upgrade it to the latest version. If it's the fact you can't restart it in game, then sorry, we've moved onto other projects that interest us after the fact, so this is presented, for the most part, as is back during the jam.
Has potential but is really sad at this point. The controls are ok but not being able to restart is silly. The items are really poorly detailed. I didn't know what I was supposed to be looking for or what survival method to utilize. Seemed like as time went on the zombies just got to be too fast and too many and I had no turret. The turret is another thing. I can kite the zombies all day but if my turret won't shoot them what is the point? Iron out the details and this could be a good bit of fun.
Turrets have a limited range, so you'll have to guide the zombies to its field of vision. As for the restart, we just didn't have the time, a good chunk of the 48 hours if I remember were spent on working on pathfinding and balancing the game. Yeah, we were playtesting each others' games.
The game refuses to load at all.
Due to the fact the game runs on HTML5, your browser has to support it. Using the latest version of Firefox, Chrome, Internet Explorer, etc. is recommended. Other than that, I'm not sure why it wouldn't run.
It's not that bad a game, though you could expand on the idea and make something really awesome