Seems cheating or getting more xp is very easy.
Just go to dat/actors and change in enemies.lua :-
- {l Code}: {l Select All Code}
-- experience_points = 15,
experience_points = 100,
Instead of changing the xp points, I commented it and started the game. I don't think compiling is needed although need to see if that's the case or not. The above ones were for spider and the slime. For playtesting purposes or just to have a quick game this is/would be a good way.
One thing I have not understood though is how the xp of the battle is calculated, does it take total of all the three slimes xp in which case I should be getting 300 xp but I'm not getting that, I get 153 xp when battling 3 slimes.
Looking forward to people's comments if the above works or not (without compiling) or is compiling needed as well as if anybody knows/has idea as to how the xp for the battle is calculated.
Update: seems the above works without compiling, just change the amt. of xp you want and when you restart it will read and take the new values from valyriatear/dat/actor/enemies.lua and start giving you the new xp level.