McZonk has ported Commander Keen to the PSP, heres the details from his blog:
<blockquote>And here it is: the news with a title. For all tried to guess the text in the news below. Try Standard Galactic Alphabet.
The font was taken from Commander Keen. An ID Game from 1990. Read more on Wikipedia or commander-keen.com
You can download it with the first shareware episode. Episode 2 & 3 are also supported but you need the original disks for it.
I began in the beginning of the last semester with porting keen to the psp. I don't know about CloneKeen at this moment. Catalin another Keen addicted guy already made an opensource windows/linux port. So I deleted all my work and just change some lines of code in clonekeen.
It is not 100% finished, some buttons need to be mapped (see the bugs in the readme) but you can play and have fun.</blockquote>