Hi,
i might be alone with that issue because i doubt no one else with my Card is playing that game.
But when i play Hedgewars on my AMD HD7850 (playing on Win7 x64) it seems like sometimes some strange Objects blink/pop up on the map. I already played Hedgewars some years ago (different Graphics card back there) and i can't remember having such an issue. So it might be related to the Drivers or the Card itself.
Btw. it also seems to be related about the screen position. If i notice smth popping up and don't move the screen away from that position sometimes it seems like it (whatever it is) will pop up again. If i move the screen it'S gone.
it's not like it's unplayable it just happens totaly random. Im already on the newest Beta Driver but the Issue seems to occur on the latest WHQL drivers too. I also play some GPU-Intense Games like Battlefield 3 and don't have issues in that games.