Spikes - Spikes can appear on any block and will hurt both heads.
Fireballs - Fireballs can either jump up from the lava or travel in a circular pattern. They will hurt both heads.
Lava - Any head that touches the lava results in game over. Some levels the lava is stationary, some levels the lava tide goes up and down, and some levels they continuously rise and force the player to be very quick.
Gates - Some later levels have gates which go up and down and will hurt any head. The player has to be very careful to pass through them while they're up, and not make contact with any metal part of the gate.
Coloured pegs - The player must use the correct colour head to connect with the peg, the wrong colour results in losing one health and unable to connect with it.
Coloured blocks - The player can step on the blocks but if they use the wrong coloured head they will lose one health.
Coloured fireballs - They travel from one tube to another and can hurt the player if they touch the opposite coloured head.