So then I was hitting enter after each #. That also seems to cause the double entry. Once I stopped clicking and hitting enter I've not seen the double entry bug.
I'm still getting these ?bugs? where the character jumps, but only makes it halfway across the pit. Always seems to happen when the pit is ~320 pixels. Maybe that is per design and I have to enter the answer earlier as the game goes on or something... [Edit] Got one where the pit was more like 255 pixels. Then I got one where I'd entered the answer for the next pit before he jumped but he still didn't clear the previous pit. Dunno if you have a log but the score was 1095 and it was about 7:50 CDT, or maybe 02:50 GMT.