Awesome, yet Impractical: The yellow mortar weapon that only appears during boss battles is ONLY meant for boss battles. It also provides free invincibility on pick-up. Trying to aim it at anything smaller than a boss will generally get you killed, as the shells fly high in the air and don't hit anything mid-arc. Despite this, in the arcade version, it can be carried into the next stage.
The arcade version is literally impossible not to die in, mostly due to slow movement speed without the speed powerup (which has a short duration). The arcade Smash TV is probably designed this way intentionally to eat up quarters. Other ports are mostly difficult for being bad ports. Despite this, one of the developers claims he can finish it in one coin.
That still doesn't manage to explain how evil this game is. Individual rooms in arenas 3 and 4 will run you over 10 minutes each, and later enemies will start to run much faster than you.
Home versions of the game were a lot more popular; the game was no less hard, but seeing as you got unlimited continues and didn't need to waste quarters, it helped a lot.