The Ad Astra demo seems to work ok. Make sure you are running the latest version (updated this year by zep) as the original version released in 2016 is not compatible with current versions of pico8 or tac08.
Yes. PNG support is on my TODO list. 😀
I used the source from this link https://www.lexaloffle.com/bbs/?pid=26835, which does not work in the emulator on my PowKiddy Q80 (I am using version 0.0.4 from Sep 9).
I could not find any newer build. of the demo