"level" is actually short for "level element". so each of those things you put in a level (characters, items, obstacles, enemies, geometry, etc) is a "level". with the emphasis on the second syllable. levél. it's a combine combine situation
if you don't feel like moving the syllable emphasis you could also just pronounce it differently. with the second vowel being an enunciated /ɛ/ in the case of the made up word I just made up meaning level element, and of course the usual /ə/ if you just mean, like. a level