This replay was made during the torrent tower bug. Basically, the level up component of damage would tack onto the standard attack, so a fully charged level 2 tidal tower would have over 10k attack added to its standard attack. At that time, the intended damage of a level 2 tidal tower was supposed to be 400 damage per shot, so you're looking at a 2683.75% increase in damage over what a tidal tower is supposed to do.
Currently, level 2 tidal towers are supposed to have 450 damage per shot, but that's still 2396.67% more damage output than intended.
I would suggest attempting the challenge on the current version. There are no major bugs at current, at least to my knowledge.
That was on the current version, at least as far as the ASIA / Pacific servers are concerned, because I just started that game and played it as normal yesterday. Doing a search for "Element" in the arcade only brings up 3 results:
"Element Tower Defence 2 v1.88", which is says is "obsolete play it without the 2",
"Element Tower Defence v1.33" which I played, and
"Element Tower Wars v1.0".
If there is a newer version out there then can someone please update the ASIC / Pacific servers with it?
Watching your demo now Venny
Oh and by the way, in case you didn't know, the loophole is disabling the auto-cast of the torrent / tsunami tower.