Reading over the actual text of the act, there are a few quirks of note. This is not written as a pro- or anti-critique, just pointing out some idiosyncracies of the law as written.
1) There is no law enforcement exemption. Police officers in New York will be in violation of the law for carrying their normal service pistols. That's sort of what happens when you ram a bill through the legislature with no public hearings or oversight. The embarassed NY legislature is working on that one.
2) There is an explicit exemption on high-capacity magazines for “curios and relics”, which is weapons (and magazines) made over 50 years ago. Which would mean that today, anything in the "high-capacity" category from 1963 or earlier is still legal (or more legal than newer items, anyway). Interesting enough, this means that the first AR-15 magazines are already legal (though good luck proving the date of manufacture), and Glocks will be legal again in 2031, though I suspect they will amend or creatively interpret the laws by then (there is some ambiguity in the word "replica" in the legislation). However, I believe that as defined in the law, weapons that have been in long production and still use the same magazines are not counted as curios, so a weapon would have to been discontinued in production by 50 years ago, or no longer use the same magazines. This would in fact disqualify weapons like old AR-15's if the old magazines would fit in new weapons or vice versa.
3) A number of .22 rimfire rifles are now "assault weapons", because their high-luster finish wooden stocks have a thumbhole in them. But, their 10-round magazines would disqualify them anyway...
4) Speaking of which, the US Olympic pistol team will not be practicing in New York anymore, since semi-auto pistols where the magazine is outside the pistol grip (like .22 rimfire Olympic pistols) are now on the bad side of the law (section 37C(IV)). These specialized .22's may also exceed the allowable weight limit for semi-auto pistols.
5) Just in case you were going to try to slip one past the governor, adding a grenade launcher to your otherwise legal semi-auto rifle does make it an assault weapon (section 37A(VII). You may, apparently, add a grenade launcher to your pistol or shotgun without running afoul of the law (section 37B and 37C).
6) It is illegal to sell a weapon to someone in New York who cannot legally own it. Since many weapons previously legal there are now illegal to sell to someone else in New York, this means the only legal sale option is out of state. Presumably, this means that New York will no longer criticize any other state for exporting gun violence...
7) Section 48.1(I) says that permits per that section shall not be issued or renewed to anyone who has stated they have ever suffered any mental illness (mental illness is not defined in the statute). So, if you're 50 and suffered a bout of depression when you were 18, whether you state this or not is up to you I guess. Likewise, no veteran diagnosed with PTSD will ever get a permit again in New York. Any effect on the willingness of NY veterans to seek help for PTSD or other problems is unknown.
8) To throw in the kitchen sink, the other list of prohibited items is (their spelling, not mine): any firearm, electronic dart gun, electronic stun gun, gravity knife, switchblade knife, pilum ballistic knife, metal knuckle knife, cane sword, billy, blackjack, bludgeon, plastic knuckles, metal knuckles, chuka stick, sand bag, sandclub, wrist-brace type sling shot or slungshot, shirken or "Kung Fu star" with intent to use the same unlawfully against another.
9) The 58 sections of the law are effective immediately, with the exceptions of sections 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,
33,34,35,36,39,41,41,42,43,45,46,47,51,52,53,54,55 and 56...
