@Dpunch444 Once in the game, click on the "character" icon, and select the character you wish to modify. in the lower right hand corner of their picture is a little set of gears, mouse-over text "Customize character." aspect is in there.
PrinceLu, if you're really stuck there's a walkthrough on kongregate, as well as comprehensive maps here: http://fighunter.wikia.com/wiki/Sandflow_Caves/Map
Hate to be a nitpicker, but after some testing in the speed up button, i realized that it speeds up the viruses more than the towers, actually making speed up mode more difficult than regular (aside from the typical reaction speed difficulty.) Was this intentional?