A Koala is not a bear.

[Whammo]

This is multicolor bitmap mode, which in addition to the bitmap and screen memory, color memory is used.
Don't get me started about the "special" character in the filenames of Koalas, it's well into the 21st century and we can rename files. Anyway, that's a sword I haven't thrown myself upon, yet.
I had an earlier version of this that loaded directly to memory. Part of the load is aligned, using the original load address, and part of the load needs to be moved according to the chosen VIC configuration. The last byte of the koala goes to the background color.
Loading it straight in can be really fast, but it's a huge file and destroys the edit buffer. But I did it just to do it, and finished with an ABORT, but that's not as much fun as not trashing things and exiting cleanly.

require gfx
require io
base @ hex
: koala bl word count   \ a different way to capture a filename
  d011 dup c@ 20 or swap c! \ It's all you, now
  d016 dup c@ 18 or swap c!
  38 d018 c! \ vic memory
  dd00 c@ %1111100 and
  dd00 c! \ vic bank

8 8 open ioabort clrchn
8 chkin ioabort
chrin chrin 2drop
1f40 0 do chrin e000 i + c! loop \ bitmap
3e8 0 do chrin cc00 i + c! loop   \ character but color
3e8 0 do chrin d800 i + c! loop  \ color memory
chrin d021 c!                                \ Background color
clrchn 8 close
key drop
0 d021 c! 7 286 c! 8 d016 c! \ lores won't quite do it
hires lores              \ there
page ;
base !

edit: I was leaving us in multicolor mode, doodles weren't displaying correctly after koalas.