Simplify the following text for a Grade 12 native English-speaking person.
Original: Unlike the Doctor 's other enemies , the Cybermen have changed a lot in appearance over the years , looking more and more modern , although retaining certain commonalities of design , the most iconic being the `` handle bars '' attached to Cybermen heads , that were supposed to aid with their hearing , their round eyeholes and their chest units .
Simplified: Unlike the Doctor 's other foes , the Cybermen costumes have changed substantially in appearance over the years , looking more and more modern , although retaining certain commonalities of design , the most iconic being the `` handle bars '' attached to Cybermen heads that were supposed to aid with their hearing . Other design elements include their round eyeholes and their chest units .