Yes, I mean too many objects/enemies. The best challenge levels use simple, clear obstacles that are as predictable as possible.
The enemies you've used on the right hand side of the second floor have a degree of randomness in their movements which is acceptable when they're placed sparingly. When you use such a volume of them in one space, though, crossing the screen is more like a game of russian roulette than a skill-based challenge; the unpredictability means that repeatedly charging through the screen blind is almost as viable a technique as attempting to dodge projectiles.
The challenge on the left-hand side of that floor suffers for being unclear to the player. Using the retractable spikes means the obstacle is impossible to see as a whole which overcomplicates it. The very same room with permanently visible spikes would still be a tricky obstacle but the threat would be apparent to the player on their first attempt.
The two problems both tie in to the same design flaw. Killing a player out-of-the-blue (whether with an obstacle that was hidden, or a random event) doesn't add to difficulty, it takes away from fairness which is just irritating for any player.