the AC source is not connected and C1 is shorted on the schematic, but since you are not making a PCB from the netlist I am sure you will be able to work around that.
the LD pin needs to be a voltage input from 0.5-2V for linear dimming, it actually sets the peak current. You are showing it as a simple variable resistor to GND.
R1 should be terminated to the gate pin of the IC and not to GND. this changes the regulation mode of this particular chip to peak current constant off time instead of constant frequency. this allows good regulation at duty cycles over 50%. Sorry I thought I had posted the link to the app note but it does not look like I did:
https://www.electro-tech-online.com/custompdfs/2008/05/AN-H50.pdf
Early in the discussion it tells about the disadvantage of current mode regulation and explaining that constant off time takes care of it and gives figure 4. the rest of the document goes into the design formulas.
Tie U1 Vin to 18V instead of 360V. The chip is capable of running that way, but it is unnecessary dissipation when you have a lower voltage rail available. The internal linear regulator is there for running LEDs off line with out extra parts.
You do not say how you are obtaining 18V. A 12V transformer can easily reach 25V under no load conditions. 20% for regulation (small transformer spec), 20% for line variation under normal (not fault) conditions, and 40% from RMS to line peak. That is sufficient to blow U2 and the FET.
That is all I am seeing off hand.