It's incredibly easy to just save up a bunch of money (like 10K) and then just leapfrog from level 50 to level 100 without really fighting all that much. The game gets really easy later on - also, spells need to be more abundant.
Not terribly difficult - it's got some back strategies to it, but it's interesting enough. It needs more customizability - special abilities for your teams, etc.
I think this game is supposed to be very artistic and whatnot, so I give it a 4/5 for being professional, having VERY nice graphics, and for holding my interest while being so simple.
As for the anti-pro-Nazi, this game isn't pro-Nazi, it's just giving a different perspective - sometimes that's necessary. Besides, the allies always win in this game - it's more of a message about perseverence.