It's not the reading comprehension level. I don't find any particular translation particularly challenging. There are words whose meanings have changed over 400+ years though, and therefore the language would be immediately clearer to people in 1611 than in 2015.
I agree.
"abased" (Matt. 23:12; Luke 14:11; 18:14) then meant "humbled"
"abide" (Acts 20:23) then meant "await"
"acquaintance" (Luke 2:44; 23:49; Acts 24:23) then meant "acquaintances"
"admiration" (Rev. 17:6) then meant "wonder"
"affections" (Gal. 5:24) then meant "passions"
"again" (Matt. 27:3; Luke 14:6) then meant "back"
"allege" (Acts 17:3) then meant present "evidence"
"allow" (Luke 11:48; Rom. 14:22; 1 Thes. 2:4) then meant "approve"
"amazement" (1 Pet. 3:6) then meant "terror"
"amend" (John 4:52) then meant "mend"
"answer" (2 Tim. 4:16) then meant "defense"
"approve" (2 Cor. 6:4; 7:11) then meant "commend" or "prove"
"assay" (Acts 9:26; 16:7; Heb. 11:29) then meant "essay" or "attempt"
"attendance" (1 Tim. 4:13) then meant "attention"
"base" (1 Cor. 1:28; 2 Cor. 10:1) then meant "lowly"
"behind" (Col. 1:24) then meant "lacking"
"bewitched" (Acts 8:9, 11) then meant "astonished"
"by and by" (Matt. 13:21; Mark 6:25; Luke 17:7; 21:9) then meant "immediately"
"careful" (Luke 10:41; Phil. 4:6) then meant "anxious"
"charged" (1 Tim. 5:16) then meant "burdened"
"charger" (Matt. 14:8, 11; Mark 6:25, 28) then meant "platter"
"charity" (1 Cor. 8:1; 13:1, 2, 3, 4, 8, 13; etc.) then meant "love"
"charitably" (Rom. 14:15) then meant "in love"
"communicate" (Gal. 6:6; Phil. 4:14, 15; 1 Tim. 6:18; Heb. 13:16) then meant "share"
"communications" (Cor. 15:33) then meant "companionship"
"concluded" (Rom. 11:32; Gal. 3:22) then meant "shut up"
"conscience" (1 Cor. 8:7; Heb. 10:2) then meant "consciousness"
"convenient" (Rom. 1:28; Eph. 5:4; Phlm. 8) then meant "fitting" or "proper"
"conversation" (2 Cor. 1:12; Gal. 1:13; Eph. 2:3; etc.) then meant "manner of life" or "conduct"
"corn" (Matt. 12:1; Mark 2:23; 4:28; etc.) then meant "grain"
"countries" (Luke 21:21) then meant "country"
"country, a" (John 11:54) then meant "the country"
"damnation" (Matt. 23:14; Mark 12:40; Luke 20:47; etc.) then meant "condemnation" or "judgment" (1 Cor. 11:29)
"damned" (Mark 16:16; Rom. 14:23; 2 Thes. 2:12) then meant "condemned" or "judged"
"delicately" (Luke 7:25) then meant "luxuriously"
"deliciously" (Rev. 18:7, 9) then meant "wantonly"
"doubtful" (Luke 12:29) then meant "anxious"
"draught" (Matt. 15:17; Mark 7:19) then meant "drain"
"earnestly" (Luke 22:56; Acts 23:1) then meant "carefully" or "steadfastly" or "intently"
"ensue" (1 Pet. 3:11) then meant "pursue"
"entreat(ed)" (Matt. 22:6; Luke 18:32; 20:11; etc.) then meant "treat(ed)"
"estate" (Acts 22:5) then meant "council"
"estates" (Mark 6:21) then meant "men of nobility or rank"
"ever, or" (Acts 23:15) then meant "before"
"evidently" (Acts 10:3) then meant "clearly" or "openly" (Gal. 3:1)
"fame" (Matt. 4:24; 9:26, 31; 14:1; Mark 1:28; etc.) then meant "report" or
"feeble-minded" (1 Thes. 5:14) then meant "fainthearted"
"forward" (2 Cor. 8:10, 17; Gal. 2:10) then meant "ready" or "eager"
"frankly" (Luke 7:42) then meant "freely"
"furnished" (Matt. 22:10) then meant "filled"
"go beyond" (1 Thes. 4:6) then meant "transgress"
"good" (1 Jn. 3:17) then meant "goods"
"goodman" (Matt. 20:11; 24:43; Mark 14:14; etc.) then meant "master"
"governor" (James 3:4) then meant "pilot"
"grudge" (James 5:9; 1 Pet. 4:9) then meant "grumble"
"guilty" (Matt. 23:18) then meant "bound"
"hardly" (Matt. 19:23) then meant "with difficulty"
"instant" (Luke 23:23) then meant "insistent," or "constant" (Rom. 12:12), or "urgent" (2 Tim. 4:2)
"keep under" (1 Cor. 9:27) then meant "buffet"
"lade" (Luke 11:46) then meant "load"
"large" (Matt. 28:12) then meant "much"
"lewd" (Acts 17:5) then meant "wicked"
"lewdness" (Acts 18:14) then meant "villainy"
"listed" (Matt. 17:12; Mark 9:13) then meant "wished"
"listeth" (John 3:8; James 3:4) then meant "wishes"
"lively" (Acts 7:38; 1 Pet. 1:3; 2:5) then meant "living"
"loft" (Acts 20:9) then meant "story"
"marred" (Mark 2:22) then meant "destroyed"
"meat" (Matt. 3:4; 6:25; 10:10; 15:37; 24:45; etc.) then meant "food"
"minister" (Luke 4:20) then meant "attendant"
"minstrels" (Matt. 9:23) then meant "flute players"
"motions" (Rom. 7:5) then meant "passions"
"observed him" (Mark 6:20) then meant "kept him safe"
"occupy" (Luke 19:13) then meant "trade"
"other" (John 21:2; Acts 15:2; 2 Cor. 13:2; Phil. 2:3) then meant "others"
"other some" (Acts 17:18) then meant "some others"
"overcharge(d)" (Luke 21:34; 2 Cor. 2:5) then meant "over burden(ed)"
"particularly" (Acts 21:19; Heb. 9:5) then meant "in detail"
"pitiful" (1 Pet. 3:8) then meant "merciful"
"presently" (Matt. 21:19; 26:53; Phil. 2:23) then meant "immediately"
"pressed out of" (2 Cor. 1:8) then meant "oppressed beyond"
"prevent" (1 Thes. 4:15) then meant "precede"
"prevented" (Matt. 17:25) then meant "spoke first to"
"profited" (Gal. 1:14) then meant "advanced"
"profiting" (1 Tim. 4:15) then meant "progress"
"proper" (Acts 1:19; 1 Cor. 7:7) then meant "own" or "beautiful" (Heb. 11:23)
"quick" (Heb. 4:12) then meant "living"
"quit you" (1 Cor. 16:13) then meant "conduct yourselves"
"reason" (Acts 6:2) then meant "reasonable"
"record" (John 1:19; Acts 20:26; 2 Cor. 1:23; Phil. 1:8) then meant "witness"
"respect, had" (Heb. 11:26) then meant "looked"
"room" (Matt. 2:22; Luke 14:7, 8, 9, 10; Acts 24:27; 1 Cor. 14:16) then meant "place"
"sardine" (Rev. 4:3) then meant "sardius"
"scrip" (Matt. 10:10; Mark 6:8; Luke 9:3; 10:4; etc.) then meant "bag"
"secondarily" (1 Cor. 12:28) then meant "secondly"
"sentence" (Acts 15:19) then meant "judgment"
"several" (Matt. 25:15) then meant "particular"
"shamefacedness" (1 Tim. 2:9) then meant "modesty" or "propriety"
"shape" (John 5:37) then meant "form"
"should" (Acts 23:27) then meant "would"
"sincere" (1 Pet. 2:2) then meant "pure"
"strange" (Acts 26:11) then meant "foreign"
"strangers of" (Acts 2:10) then meant "visitors from"
"string" (Mark 7:35) then meant "band"
"study" (1 Thes. 4:11; 2 Tim. 2:15) then meant "strive"
"tables" (Luke 1:63; 2 Cor. 3:3) then meant "tablets"
"take no thought" (Matt. 6:25, 28, 31, 34; 10:19; Luke 12:11, 22, 26) then meant "be not anxious"
"taking thought" (Matt. 6:27; Luke 12:25) then meant "being anxious"
"temperance" (Acts 24:25; Gal. 5:23; 2 Pet. 1:6) then meant "self-control"
"temperate" (1 Cor. 9:25; Tit. 1:8) then meant "self- controlled"
"translated" (Col. 1:13; Heb. 11:5) then meant "transferred"