Gameplan:
Draw through your deck using bloodmage thalnos, Ice fishing, far sight, and mana tide totem
Use board control spells like volcano, lightning storm, and rain of toads to stay alive until you can pull off your combo.
Combo:
Play 2 galvanizers beforehand to reduce the cost of your mecha’thun to 8
Empty your hand except for damage dealing spells, then play and kill mecha’thun
examples of spell combos are 2x zap 2x lightning bolt or 1x zap 1x crushing hand