Zombie vs. Ambulance!

Zombie vs. Ambulance (PS2, Japan Only)
Simple 2000 series Vol. 95, Zombie vs. Kyukyusha

A mysterious bacteria has spread across town and turned most residents into zombies. You play as a doctor who must ride through town in an ambulance and rescue survivors, bringing them back to your center of operations at the hospital. By saving mechanics, you earn parts which can be used to upgrade your vehicle.

From Chris' Survival Horror Quest:

The basic formula is leave the hospital -> run over some zombies and help some people -> return to the hospital, repeated over and over. But the need to run zombies over to win keeps the tension level high, so I think the system works pretty well.

First of all, there's a "hospital health gauge." As you drive around the gauge is slowly depleted, and if it ever goes to zero it means the hospital has succumbed to the zombies and it's game over. It's basically a life bar for the hospital. In order to fill the gauge back up, you have two options:

• You can run over a lot of zombies and get combos, or
• You can save police and military personnel.

This mechanic keeps you on your toes.
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The ambulance upgrades are cool. You can get mechanics that you save to upgrade your ambulance, but they'll require you to complete their weird requests (like, "run over 40 zombies to finish this upgrade") first. This is another reason to keep running over zombies, and combined with the hospital's health gauge, there's a nice balance that keeps the game from getting dull. It's a good combination.
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If you don't get survivors that you've picked up back to the hospital before the time runs out, they'll turn into zombies inside the ambulance. This makes the ambulance harder to drive. How are you supposed to solve this problem? By driving full speed into a wall, which causes the zombies to fly out of the vehicle! WTF.

Here's the official site, and if you've got the means to play it, you can buy it here!

Thanks to Sam for the tip!