Haha glad the cats worked for you I had to put them in there.
There actually are graphics settings in the game with low medium high and ultra. I think you probably had it on ultra which could explain the lag and the fans going crazy. I usually played on high myself.
The menu is a bit weird though. For some reason Escape doesnt always open it properly in fullscreen and sometimes just messes with the window instead. If you switch out of fullscreen you should be able to open the menu and go into settings to change the quality. So yeah thats definitely something I should fix too.
And thanks for mentioning the visuals. I wanted to do more with them but the project got pretty big and I ran out of time for some of the polish.
Also thanks for playing and for the feedback :) If you ever try it again on a lower quality setting Id be curious if it runs better for you.