I've been using the Nintendo 3DS for 2 days now (not straight!) And believe me it is amazing! Incredible in every way. However one big big big issue with the device became apparent after playing with it for only a mere 15 minutes. It strains my eyes and always gives me migraines/head aches. I was curious to find out whether or not it was just me, so i took the device to the 'Cheadle Hulme School' to test it out on some students. They all loved it, but agreed it gave you eye strain within 10 minutes on average (10/13 students agreed).
As well as this the 3DS repeats itself and emphasises the importance of not over playing on the 3D mode. Hmmmm maybe this might be the fall of the 3DS...keep checking out this spot to see for a full review on the device.
