Your graphics and UI won't look good/work on all browsers without a lot of pain. Have you ever tried to make something cross-browser? Getting the same results in the last few versions of IE and Firefox is difficult enough! Flash would be ideal for this type of web game.
I played around with a (free) Perl module which generated flash movies a few years ago when I was interested in making an online PerlRobots game: battles between bots would be simulated nightly and flash animations would be posted to the site to showcase the results.
I played around with a (free) Perl module which generated flash movies a few years ago when I was interested in making an online PerlRobots game: battles between bots would be simulated nightly and flash animations would be posted to the site to showcase the results.