There should be a way to exchange resources for coal, as you don't need iron at all after the first two upgrades (though I haven't finished the game yet, so I don't know for sure). Maybe 3Iron:Coal 2Tint:Coal 1Urain:Coal 1Diam:2Coal 10gold:Coal? Bones should not be tradeable :P
All in all, a good game that could be made way better, such as in game achievements and a more unique upgrade system. But although it has many similarities to Burrito Bison, I'll say 4/5.
On gnok yeknod with the cannons that shoot bouncing spike balls, I hate how when you hit them they bounce off you... It's almost like they're taunting you... but still :)
I think that in SCGMD5 there should be a total hit notes counter or maybe just a stats page but great game, have been playing this for years now (with breaks :P) keep it up! 5/5
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