You may be able to solve the problem by running a local web server, without digressing through PDF / Preview or changing code.
(1) In TERMINAL, navigate to the directory where you exported the Keynote into HTML in the first place. This directory will contain an index.html file directly under it.
Thus, if the HTML export is called "keythings", after the prompt ($) in TERMINAL type "cd", as follows:
$ cd
(2) then go to a FINDER window and simply drag the directory noted above into the active line in Terminal, leaving a space between "cd" and the dragged name. Conveniently this will result in a line as follows (without requiring you to type the filepath...and make mistakes):
$ cd /Users/yourname/directoryinquestion
that will move the terminal program's active site into the directory.
(3) Then start the server as follows, again using TERMINAL:
$ python -m SimpleHTTPServer 8888 & <enter>
This will start the internal / local web server. The port-number (here 8888) could be substituted arbitrarily, as long as it doesn't go too low, where there are designated ports for other functions. So you can use 8889 etc.
(4) Go to the BROWSER (Chrome, Safari ...) and type localhost:8888. This will display the contents of index.html, which should automatically bring up the Keynote slides (though without all the extra movement, etc., you may have used), driven by the html code. This HTML can be altered with an editor in the index.html file, resaved, and that can supplement or change the effects, if you need them...using HTML itself, CSS, Javascript etc.
(5) Don't close the Terminal window until you're done with the browser representation of Keynote.
At least this works for me...I hope it is useful.