Ah, Thanks for playing. You are right, the first boss might be a bit too difficult.
The boss has 3 attacks. the first attack is when the boss moves left and then right to the wall, and then back to center. This is the easiest pattern, you can jump as soon as the boss touches the right wall.
The second attack is when the boss bounces around, each bounce toggles the spike. This is the hardest attack i feel like. You can try to safely ignore this attack.
The third attack, the boss goes up and slams down and does that another time, the second time the spikes go down, so you have a lot of time to jump on him.
After each attack, the boss goes back to the center.