I tried level 1 on the server and both levels on the itch page. On the itch page, level 2 had a lag spike toward the end that caused it to drop to 8 fps for a couple seconds, but that didn't effect gameplay. Besides that, both stayed around 45-55 fps the whole time.
It's hard to tell where I can and can't place rocks to block paths or whether I've succeeded to block a path. Other that that, the shield symbol and the rock symbol are very similar, which confused me at first when I was trying to figure out the costs of things. The game also seems oddly slow-paced for a tower defense game, but not so much as to not be enjoyable. Overally I like it so far.