These are the levels of the first Battletoads game:

Level 1: Ragnarok's Canyon
It is the easiest level. The abilities needed here are fighting and avoiding falling into pits. It has an easy boss. The toads must pick a stone the robot fires and to throw it at it. They then enter a pit.
Level 2: Wookie Hole
This pit is full of vultures and piranha plants. The toads are hanging from a rope and they have a new move: they can transform into a pendulus by touching the walls. They can attack now and kill immediately. There is a trick on this level to get a lot of lifes: the player must attack a vulture and he must keep attacking it (make sure it doesn't leave the screen) until it gives a life. He also wins a lot of points. The lifes earned here will be very useful on the next level, which is a hard one.
Level 3: Turbo Tunnel
The difficulty is rapidly increased here. The toads must drive a motorcycle and must evade a lot of walls. They must also avoid falling into pits. It is very hard, a good memory and synchronization is required. At the end phase, the player can be warped 2 levels in advance if they touch the tenth wall.
Level 4: Arctic Caverns

A snow level with snowmen and many pits and hazards. The player must use snowballs to destroy walls to advance in some parts. He must avoid falling and touching spikes.

Level 5: Surf's City
A surf level where the toads must evade spikes. It is not as hard as Turbo Tunnel though. The toads lose a life if they touch the spikes, but they are not hard to evade.
Level 6: Karnath's Lair
A snake level. The toads must climb and ride snakes to get to the end. They must avoid falling and touching spikes, as always. It is divided in four phases. If the player dies, he will repeat the last phase, not the entire level.
Level 7: Volkmire's Inferno
A hard level in which the player drives a spaceship. The toads must avoid electricity. Be careful with timing and moving very fast.
Level 8: Intruder Excluder
A maze level with lots of traps. The enemies are mostly electrical robots. Everything is electrical. Robomanus awaits at the end.
Level 9: Terra Tubes
A very hard, huge maze-like level, half filled with water, with electrical enemies, spikes and rolling tubes.
Level 10: Rat Race
There are bombs that some rats can activate and kill the toads. The toads must race them and win. When the toads win, they can activate the bomb and can kill the rats. There are three rats to bomb. After the rats, the toads will have to fight a boss. This boss is easy to beat. The toads must only attack him while he is on any side, next to the walls. That way it will jump and the toads will pass below, untouched. Repeat it until the boss is defeated.
Level 11: Clinger-Winger

A very hard level. The player must ride a monocycle and must race through a maze. He must move exactly as the path indicates. He must not fail to move as it is. If he makes bad moves, he will soon be reached by a coloured circle which will kill him mercilessly. At the end of the level, the toads can take revenge and will have to fight the circle.

Level 12: The Revolution
The last but not the least! This is a large tower in which the player must fight enemies, must avoid falling and must hang from a pole if an enemy tries to blow at him. At the top of the tower, the Dark Queen herself awaits. And she will not bake a cake for a welcome! If the toads defeat her, Angelica and Pimple will fall and the game is over! Congratulations if you get this far!