EXTRA TIP: Play time attack and you will have many money as you kill and survive them.You will not receive any penalty when you get defeated too. Click + to keep this comment alive!
I have something to add in the energy shop: Tall World (50x400) that costs 2000 energy , Spikes (Lets you restart if hit) that costs 1750 energy , Re-Summon (Lets you restart here if you hit with a spike) that costs 1000 energy and Melting Block (Melts SLOWLY) costs 1500 energy