@ 4 years ago or so best i recall
Different stock, including choice between wood and synthetic.Different trigger assemblyBolt can be switched to left hand side.Different breech design.Different baffle design in shroud.There may have been some valve design changes, but gen1 and gen2 valves are interchangeable.Different trigger guard shape.Rear air tube cap is completely different.
From the Pyramyd Air site: Upgrades from the original version of the gun: Factory-installed depinger changes the sharp "ping" to a dull thud. Improved valve (increases the number of shots: .177/.22=32 shots, .25=16 shots). Trigger moved back for better hand position. Optional reversible bolt for left- or right-handed shooters. Simplified breech design for assembly, service and to provide a more stable platform for larger scopes.
Like the idea of keeping the chronology of a popular airgun....something that "we"don't really do well even with all the information scattered around here and there.But it really boils down to what the ened users actually found to be "better"and not the marketing.So a search though the posts of that time,with onwers wondering if they should "up grade"to the new versions, is probably the mother load of the data mine.------------Memory fragment:First year of the Gen I, there was a trigger breakage problem.....they had an "almost recall" (don't think it every got to that status,but they did offer to up grade).
From Crosmanhttps://www.crosman.com/discover/airguns/airgun-innovation
The Gen 2 came out in 2013 according to Crosman Parts lists and files. The Gen 1 valve will not fit a Gen 2 unless you cut a channel or drill depressions for the trigger screws. Pics, Gen1 left, Gen2 right. Most of the trigger parts are interchangeable but the sears are different because the trigger location was slightly changed.
The breech blocks are very different, as necessitated by the change to the bolt that allows for easy swap form RH to LH operation (easy, but disassembly of the upper is required). The leads to different pros and cons for both designs.The Gen I has a three screw mount, and Gen I is 4 screws (two at the rear of the block, vs, 1 at the rear on Gen I). To get that rear screw out on Gen I, you have to remove a small cap (puts pressure on the bolt) and the bolt too - not a big deal, but annoying if all you want to do is get to the hammer retention screw.On the plus side for the Gen I breech and bolt system, you can easily remove the bolt and then have straight access thru the bore for a rod or anything. Of course the plus side on the Gen II is the easy LH operation (if that applies to you) and arguably better mounting of the breech block to the tube.One other difference between them not listed is the rear tube cap is different. I personally like the one on the Gen I better as it is a nice flat and comfortable place to put your thumb for good leverage while cocking the gun.The Gen II has much better ergonomics than Gen I (stock wrist to trigger position) but many of us Gen I shooters that really cared "fixed" that with a Boyd's stock.