What is the maximum level in challenge mode?

What is the maximum level on challenge mode? I presume it is the same on both maps currently available?

I first thought it was level 20 but last night I saw 2 players at lvl 21 and 99 on the online leaderboards. Is this a hack?

Solution 1:

Magickapedia says that there is only 20 levels.

So any more than this is probably a hack.

There have been issues where (as of 1.3.4.0) where Chapter 3 only includes the end boss fight. The temporary fix for this includes editing the XML documentation to state what level to start at. It wouldn't surprise me if the challenge XML files can be edited as well. Possibly to have multiple low enemy levels or high point enemies with added player advantages.

Solution 2:

As of this post, the top two scores are over 2 billion. I don't think there can be much doubt that they are hacked, as that would require an average of over 10 million points per level in an unmodified game.

They are also suspiciously close to the 2.147 billion mark, which in many games is the highest number that can be expressed; go any higher and it starts over form 0, or negative 2.147 billion.