Tortoise and a mammoth can be killed... I sent my hero to the turttle and let the towers and knights to get rid of the mammoth, using meteor and berserk spells with the latter.
For all of you who have lost your saved files, try updating your flash player at adobe's website. There are maney players complaining about the skull catching levels, and many other playes giving helpful tips to get those medals... so, read the comments. If it takes you a lot of time to get enough money for new parts, try getting medals with money rewards or choose a better city for your grinding (like Beijing). We know the game is hard, we didn't want to make a 15 minutes game, but still: Hundreds of players have got all the medals, and even 90 players have finished the game in 25 days or less (thanks to Siberia level), so it is possible to get your badges.
Here's a very useful tip to get the "Whale of a Tale Badge": Once you get a combo, don't lose it. You will get a lot more points from sailors, fishes and birds eaten in a combo. Also aliens give a lot of points, and they are considered sailors, so eat them in a combo. I got almost 2 million points that way (on notdoppler's scoreboard).
sorry! I forgot to publish. Now is fixed.
Some people may have problems with the control scheme. Press change controls to switch them. It has something to do with the brain hemispheres...