We tested this nice little arcade game, it's fun, but seems to run slow even our fast PC. Strange for a relatively simple game. Why is that? Is Unity's Windows executable publish not optimized or what?
The one currently on the website is built with an older version of Unity. We have made, mildly said, quite a few improvements to performance on windows since then. Really soon now there will be updated examples on the website.
On a second look - my bad, somehow I did not pay much attention to the topic. I though you was talking about the game example on otee.dk site. OpenFire is built with a quite recent version and it should be fast. I get between 80 and 200 FPS here (P4 3GHz, Radeon 9800Pro) depending on the amount of tanks/explosions on screen. What computer are you using?
AMD 64 3000+ nvidia 6100 128MB all latest drivers and DX9c. FPS was so slow at times and the cursor would freeze or be slow to change position.