I feel that the game is uneven. There are basically two tactics to beat the game. 1. focusing on attacks and 2. focusing on defence where defence is the fastest/best. If I try and mix the both, I always find myself being run over.
It's too easy. You get fully upgraded by lvl 14 with only using the C-attack. It gets a bit harder at lvl 18 but by then then you are just spamming the X-attack (which is over powered). Also, you never have to bother collecting the coins until end of lvl. A time limit on the coins would increase the difficulty. 3/5.
I really enjoyed this. A bit too much cryptology (but then again I learnt something) and the last question was a bit odd. I'd say that this is a 3,5/5, but I am guessing that alot of ppl will undeservingly rate this a 1/5, so I'm rating it a 5/5.