Yesterday I tried 0.80.1344 and I immediately noticed a considerable difference in one of my games:

0.70.6 (~55fps)

0.80 (~30fps)

I haven't tested this on previous 0.80 versions. Only the latest.

I don't know if this is a TIC-80 problem or a problem on my end. It's possible that this is caused by my ATI Radeon HD 4070 being old and no longer well supported by TIC-80. If this happens to more people, then it's probably not a problem on my end.

I created the small test below. Timing that empty loop in 0.70.6 I get on average ~49.5ms, while on 0.80 it's ~69.5ms.

local fmt=string.format
local t=0
local total=0
function TIC()
   t=t+1
   cls()

   local t1=time()
   for i=1,5000000 do
      --deliberately empty
   end
   local t2=time()-t1
	
   print(fmt("time    - %.2fms",t2),0,8,15,true)
	
   -- average
   total=total+t2
   print(fmt("average - %.2fms",total/t),0,24,14,true)
end