Cheese method
Before pressing Play, press F12 to open the console and enter the following:
var r = cr_getC2Runtime();
r.all_global_vars[1].data = 10;
Click Play, Continue, then open each level for one achievement each.
Lastly, enter the following for the final achievement:
r.changelayout = r.layouts['end'];
You can also edit most values in the game, such as starting money, tower attributes, and enemy attributes. For example, to start level 10 with high money, cheap superpowered 10th tower, and weak but fast enemies (enter this before opening the level):
r.all_global_vars[18].data=99999;// starting money
r.all_global_vars[37].data=1;// tower 10 price
r.all_global_vars[92].data=999;// tower 10 range
r.all_global_vars[93].data=999;// tower 10 damage
r.all_global_vars[94].data=999;// tower 10 speed
// All enemies 1 life and high speed
for (var i = 38; i < 65; i += 1) {
r.all_global_vars[i].data = (i+1)%3 ? 1 : 999;
}
