This was fun, a mixed bag to be sure but a good game nonetheless.
While the sprites were very lively it's sad to see the font was just the default. But on the other hand there were a lot of small details such as the timer switching to milliseconds during the last minute.
The song may have been generic, but it was catchy enough to listen to for 5 minutes!
Sprinting was a nice addition, breeding wasn't obvious but you could eventually figure it out if you stayed in the pen for long enough. Speaking of staying in the pen for long enough...
There's a minor exploit which you can use to get really high scores. The Deers counter goes up whenever a dear is placed in the pen. That means you can pick up a dear you've already placed and place it again to get more points.
But all in all 5 minutes felt a shorter, it was a strangely addictive game, at least for me. Good job, hope you develop this game further in the future (^_^)