The levels are unlimited now :P, it will just take a lot of time because the mobs will eventually give 0.001% of exp to level. Keep in mind that the saves won't persist between updates on the web version, so if you really want to put your time into it, then I suggest desktop version.
Exp requirement will eventually overflow the integer limit. Also the player killers scale beyond player possibility; even with maxed accuracy it's still 90% dodges.
